Screening and characterization of vaginal fluid donations for vaginal microbiota transplantation - Scientific Reports - 2022
Bacterial vaginosis (BV), the overgrowth of diverse anaerobic bacteria in the vagina, is the most common cause of vaginal symptoms worldwide. BV frequently recurs after antibiotic therapy, and the best probiotic treatments only result in transient changes from BV-associated states to “optimal” communities dominated by a single species of Lactobacillus. Therefore, additional treatment strategies are needed to durably alter vaginal microbiota composition for patients with BV. Vaginal microbiota transplantation (VMT), the transfer of vaginal fluid from a healthy person with an optimal vaginal microbiota to a recipient with BV, has been proposed as one such alternative. However, VMT carries potential risks, necessitating strict safety precautions. Here, we present an FDA-approved donor screening protocol and detailed methodology for donation collection, storage, screening, and analysis of VMT material. We find that Lactobacillus viability is maintained for over six months in donated material stored at – 80 °C without glycerol or other cryoprotectants. We further show that species-specific quantitative PCR for L. crispatus and L. iners can be used as a rapid initial screening strategy to identify potential donors with optimal vaginal microbiomes. Together, this work lays the foundation for designing safe, reproducible trials of VMT as a treatment for BV.
Yockey LJ, Hussain FA, Bergerat A, Reissis A, Worrall D, Xu J, Gomez I, Bloom SM, Mafunda NA, Kelly J, Kwon DS, Mitchell CM.
Fecal Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-Cov-2) RNA Is Associated With Decreased Coronavirus Disease 2019 (COVID-19) Survival - Clinical Infectious Diseases - 2022
The clinical significance of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) RNA in stool remains uncertain. We found that extrapulmonary dissemination of infection to the gastrointestinal tract, assessed by the presence of SARS-CoV-2 RNA in stool, is associated with decreased coronavirus disease 2019 (COVID-19) survival. Measurement of SARS-CoV-2 RNA in stool may have utility for clinical risk assessment.
Das Adhikari U, Eng G, Farcasanu M, Avena LE, Choudhary MC, Triant VA, Flagg M, Schiff AE, Gomez I, Froehle LM, Diefenbach TJ, Ronsard L, Lingwood D, Lee GC, Rabi SA, Erstad D, Velmahos G, Li JZ, Hodin R, Stone JR, Honko AN, Griffiths A, Yilmaz ÖH, Kwon DS.
Cysteine dependence of Lactobacillus iners is a potential therapeutic target for vaginal microbiota modulation - Nature Microbiology - 2022
Vaginal microbiota composition affects many facets of reproductive health. Lactobacillus iners-dominated microbial communities are associated with poorer outcomes, including higher risk of bacterial vaginosis (BV), compared with vaginal microbiota rich in L. crispatus. Unfortunately, standard-of-care metronidazole therapy for BV typically results in dominance of L. iners, probably contributing to post-treatment relapse. Here we generate an L. iners isolate collection comprising 34 previously unreported isolates from 14 South African women with and without BV and 4 previously unreported isolates from 3 US women. We also report an associated genome catalogue comprising 1,218 vaginal Lactobacillus isolate genomes and metagenome-assembled genomes from >300 women across 4 continents. We show that, unlike L. crispatus, L. iners growth is dependent on L-cysteine in vitro and we trace this phenotype to the absence of canonical cysteine biosynthesis pathways and a restricted repertoire of cysteine-related transport mechanisms. We further show that cysteine concentrations in cervicovaginal lavage samples correlate with Lactobacillus abundance in vivo and that cystine uptake inhibitors selectively inhibit L. iners growth in vitro. Combining an inhibitor with metronidazole promotes L. crispatus dominance of defined BV-like communities in vitro by suppressing L. iners growth. Our findings enable a better understanding of L. iners biology and suggest candidate treatments to modulate the vaginal microbiota to improve reproductive health for women globally.
Bloom SM, Mafunda NA, Woolston BM, Hayward MR, Frempong JF, Abai AB, Xu J, Mitchell AJ, Westergaard X, Hussain FA, Xulu N, Dong M, Dong KL, Gumbi T, Ceasar FX, Rice JK, Choksi N, Ismail N, Ndung’u T, Ghebremichael MS, Relman DA, Balskus EP, Mitchell CM, Kwon DS.
Prediction of Antimicrobial Resistance in Clinical Enterococcus faecium Isolates Using a Rules-Based Analysis of Whole - Genome Sequences - Antimicrobial Agents and Chemotherapy - 2022
Enterococcus faecium is a major cause of clinical infections, often due to multidrug-resistant (MDR) strains. Whole-genome sequencing (WGS) is a powerful tool to study MDR bacteria and their antimicrobial resistance (AMR) mechanisms. In this study, we used WGS to characterize E. faecium clinical isolates and test the feasibility of rules-based genotypic prediction of AMR. Clinical isolates were divided into derivation and validation sets. Phenotypic susceptibility testing for ampicillin, vancomycin, high-level gentamicin, ciprofloxacin, levofloxacin, doxycycline, tetracycline, and linezolid was performed using the Vitek 2 automated system, with confirmation and discrepancy resolution by broth microdilution, disk diffusion, or gradient diffusion when needed. WGS was performed to identify isolate lineage and AMR genotype. AMR prediction rules were derived by analyzing the genotypic-phenotypic relationship in the derivation set. Phylogenetic analysis demonstrated that 88% of isolates in the collection belonged to hospital-associated clonal complex 17. Additionally, 12% of isolates had novel sequence types. When applied to the validation set, the derived prediction rules demonstrated an overall positive predictive value of 98% and negative predictive value of 99% compared to standard phenotypic methods. Most errors were falsely resistant predictions for tetracycline and doxycycline. Further analysis of genotypic-phenotypic discrepancies revealed potentially novel pbp5 and tet(M) alleles that provide insight into ampicillin and tetracycline class resistance mechanisms. The prediction rules demonstrated generalizability when tested on an external data set. In conclusion, known AMR genes and mutations can predict E. faecium phenotypic susceptibility with high accuracy for most routinely tested antibiotics, providing opportunities for advancing molecular diagnostics.
Anahtar MN, Bramante JT, Xu J, Desrosiers LA, Paer JM, Rosenberg ES, Pierce VM, Kwon DS.
Comparison of the Vaginal Microbiota in Postmenopausal Black and White Women - The Journal of Infectious Diseases - 2021
Background: We compared vaginal microbial communities in postmenopausal black and white women. Methods: Shotgun sequencing of vaginal swabs from postmenopausal women self-identified as black or white was compared using MiRKAT. Results: Vaginal community dominance by Lactobacillus crispatus or Lactobacillusgasseri was more common in 44 postmenopausal black women (n = 12, 27%) than among 44 matched white women (n = 2, 5%; P = .01). No individual taxa were significantly more abundant in either group. Conclusions: We identified small overall differences in vaginal microbial communities of black and white postmenopausal women. L. crispatus dominance was more common in black women.
Hudson PL, Ling W, Wu MC, Hayward MR, Mitchell AJ, Larson J, Guthrie KA, Reed SD, Kwon DS, Mitchell CM.
Smoking and Human Immunodeficiency Virus 1 Infection Promote Retention of CD8+ T Cells in the Airway Mucosa - American Journal of Respiratory Cell and Molecular Biology - 2021
Smoking and human immunodeficiency virus 1 (HIV-1) infection are risk factors for chronic obstructive pulmonary disease (COPD), which is among the most common comorbid conditions in people living with HIV-1. HIV-1 infection leads to persistent expansion of CD8+ T cells, and CD8+ T cell-mediated inflammation has been implicated in COPD pathogenesis. In this study, we investigated the effects of HIV-1 infection and smoking on T-cell dynamics in patients at risk of COPD. BAL fluid, endobronchial brushings, and blood from HIV-1 infected and uninfected nonsmokers and smokers were analyzed by flow cytometry, and lungs were imaged by computed tomography. Chemokines were measured in BAL fluid, and CD8+ T-cell chemotaxis in the presence of cigarette smoke extract was assessed in vitro. HIV-1 infection increased CD8+ T cells in the BAL fluid, but this increase was abrogated by smoking. Smokers had reduced BAL fluid concentrations of the T cell-recruiting chemokines CXCL10 and CCL5, and cigarette smoke extract inhibited CXCL10 and CCL5 production by macrophages and CD8+ T-cell transmigration in vitro. In contrast to the T cells in BAL fluid, CD8+ T cells in endobronchial brushings were increased in HIV-1-infected smokers, which was driven by an accumulation of effector memory T cells in the airway mucosa and an increase in tissue-resident memory T cells. Mucosal CD8+ T-cell numbers inversely correlated with lung aeration, suggesting an association with inflammation and remodeling. HIV-1 infection and smoking lead to the retention of CD8+ T cells within the airway mucosa.
Corleis B, Cho JL, Gates SJ, Linder AH, Dickey A, Lisanti-Park AC, Schiff AE, Ghebremichael M, Kohli P, Winkler T, Harris RS, Medoff BD, Kwon DS.
Antigen Presenting Cells Link the Female Genital Tract Microbiome to Mucosal Inflammation, With Hormonal Contraception as an Additional Modulator of Inflammatory Signatures - Frontiers in Cellular and Infection Microbiology - 2021
The microbiome of the female genital tract (FGT) is closely linked to reproductive health outcomes. Diverse, anaerobe-dominated communities with low Lactobacillus abundance are associated with a number of adverse reproductive outcomes, such as preterm birth, cervical dysplasia, and sexually transmitted infections (STIs), including HIV. Vaginal dysbiosis is associated with local mucosal inflammation, which likely serves as a biological mediator of poor reproductive outcomes. Yet the precise mechanisms of this FGT inflammation remain unclear. Studies in humans have been complicated by confounding demographic, behavioral, and clinical variables. Specifically, hormonal contraception is associated both with changes in the vaginal microbiome and with mucosal inflammation. In this study, we examined the transcriptional landscape of cervical cell populations in a cohort of South African women with differing vaginal microbial community types. We also investigate the effects of reproductive hormones on the transcriptional profiles of cervical cells, focusing on the contraceptive depot medroxyprogesterone acetate (DMPA), the most common form of contraception in sub-Saharan Africa. We found that antigen-presenting cells (APCs) are key mediators of microbiome-associated FGT inflammation. We also found that DMPA is associated with significant transcriptional changes across multiple cell lineages, with some shared and some distinct pathways compared to the inflammatory signature seen with dysbiosis. These results highlight the importance of an integrated, systems-level approach to understanding host-microbe interactions, with an appreciation for important variables, such as reproductive hormones, in the complex system of the FGT mucosa.
Byrne EH, Farcasanu M, Bloom SM, Xulu N, Xu J, Hykes BL Jr, Mafunda NA, Hayward MR, Dong M, Dong KL, Gumbi T, Ceasar FX, Ismail N, Ndung’u T, Gosmann C, Ghebremichael MS, Handley SA, Mitchell CM, Villani AC, Kwon DS.
Modeling the temporal dynamics of cervicovaginal microbiota identifies targets that may promote reproductive health - Microbiome - 2021
Background: Cervicovaginal bacterial communities composed of diverse anaerobes with low Lactobacillus abundance are associated with poor reproductive outcomes such as preterm birth, infertility, cervicitis, and risk of sexually transmitted infections (STIs), including human immunodeficiency virus (HIV). Women in sub-Saharan Africa have a higher prevalence of these high-risk bacterial communities when compared to Western populations. However, the transition of cervicovaginal communities between high- and low-risk community states over time is not well described in African populations.
T cell-tropic HIV efficiently infects alveolar macrophages through contact with infected CD4+ T cells - Scientific Reports Journal - 2021
Alveolar macrophages (AMs) are critical for defense against airborne pathogens and AM dysfunction is thought to contribute to the increased burden of pulmonary infections observed in individuals living with HIV-1 (HIV). While HIV nucleic acids have been detected in AMs early in infection, circulating HIV during acute and chronic infection is usually CCR5 T cell-tropic (T-tropic) and enters macrophages inefficiently in vitro. The mechanism by which T-tropic viruses infect AMs remains unknown. We collected AMs by bronchoscopy performed in HIV-infected, antiretroviral therapy (ART)-naive and uninfected subjects. We found that viral constructs made with primary HIV envelope sequences isolated from both AMs and plasma were T-tropic and inefficiently infected macrophages. However, these isolates productively infected macrophages when co-cultured with HIV-infected CD4+ T cells. In addition, we provide evidence that T-tropic HIV is transmitted from infected CD4+ T cells to the AM cytosol. We conclude that AM-derived HIV isolates are T-tropic and can enter macrophages through contact with an infected CD4+ T cell, which results in a productive infection of AMs. CD4+ T cell-dependent entry of HIV into AMs helps explain the presence of HIV in AMs despite inefficient cell-free infection and may contribute to AM dysfunction in people living with HIV.
Schiff AE, Linder AH, Luhembo SN, Banning S, Deymier MJ, Diefenbach TJ, Dickey AK, Tsibris AM, Balazs AB, Cho JL, Medoff BD, Walzl G, Wilkinson RJ, Burgers WA, Corleis B, Kwon DS.
Persistence and Evolution of SARS-CoV-2 in an Immunocompromised Host - New England Journal of Medicine - 2020
A 45-year-old man with severe antiphospholipid syndrome complicated by diffuse alveolar hemorrhage,1 who was receiving anticoagulation therapy, glucocorticoids, cyclophosphamide, and intermittent rituximab and eculizumab, was admitted to the hospital with fever (Fig. S1 in the Supplementary Appendix, available with the full text of this letter at NEJM.org). On day 0, Covid-19 was diagnosed by SARS-CoV-2 reverse-transcriptase–polymerase-chain-reaction (RT-PCR) assay of a nasopharyngeal swab specimen, and the patient received a 5-day course of remdesivir (Fig. S2). Glucocorticoid doses were increased because of suspected diffuse alveolar hemorrhage. He was discharged on day 5 without a need for supplemental oxygen…. (con’t.)
A Single Human V H-gene Allows for a Broad-Spectrum Antibody Response Targeting Bacterial Lipopolysaccharides in the Blood - Cell Reports Journal - 2020
B cell receptors (BCRs) display a combination of variable (V)-gene-encoded complementarity determining regions (CDRs) and adaptive/hypervariable CDR3 loops to engage antigens. It has long been proposed that the former tune for recognition of pathogens or groups of pathogens. To experimentally evaluate this within the human antibody repertoire, we perform immune challenges in transgenic mice that bear diverse human CDR3 and light chains but are constrained to different human VH–genes. We find that, of six commonly deployed VH sequences, only those CDRs encoded by IGHV1-2∗02 enable polyclonal antibody responses against bacterial lipopolysaccharide (LPS) when introduced to the bloodstream. The LPS is from diverse strains of gram-negative bacteria, and the VH-gene-dependent responses are directed against the non-variable and universal saccrolipid substructure of this antigen. This reveals a broad-spectrum anti-LPS response in which germline-encoded CDRs naturally hardwire the human antibody repertoire for recognition of a conserved microbial target.
Sangesland M, Yousif AS, Ronsard L, Kazer SW, Zhu AL, Gatter GJ, Hayward MR, Barnes RM, Quirindongo-Crespo M, Rohrer D, Lonberg N, Kwon D, Shalek AK, Lingwood D.
The cervicovaginal mucus barrier to PET Imaging Reveals Early Pulmonary Perfusion Abnormalities in HIV Infection Similar to Smoking - Journal of Nuclear Medicine - 2020
RATIONALE: COPD is the most common non-infectious pulmonary disease among people living with HIV, independent of smoking. However, the cause for this enhanced susceptibility remains unclear, and the effects of HIV on pulmonary perfusion and ventilation are unknown. METHODS: We used PET-CT in 46 smokers and non-smokers, 23 of whom had documented HIV infection. Emphysema was assessed by CT and perfusion by nitrogen-13 (13NN) PET scans. After removal of image noise, vertical and axial gradients in perfusion were calculated. We tested for differences in the total spatial heterogeneity of perfusion (CV2Qtotal) and its components (CV2Qtotal = CV2Qvgrad (vertical gradient) + CV2Qzgrad (axial gradient) + CV2Qr (residual heterogeneity)) among groups. RESULTS: There were no significant differences in demographic parameters among groups, and all subjects had minimal radiographic evidence of emphysema. Compared to controls, non-smokers living with HIV had a significantly greater CV2 Qr/ CV2Qtotal (0.48 vs 0.36, P = 0.05) and reduced CV2Qvgrad/ CV2Qtotal (0.46 vs 0.65, P = 0.038). Smokers also had a reduced CV2Qvgrad/ CV2Qtotal, however, there was no significant difference in CV2Qvgrad/ CV2Qtotal between smokers living with and without HIV (0.39 vs 0.34, P = 0.58), despite a decreased vertical perfusion gradient (Qvgrad) in smokers living with HIV. CONCLUSION: In non-smokers living with well-controlled HIV and minimal radiographic emphysema, HIV infection contributes to pulmonary perfusion abnormalities similar to smokers. These data indicate the onset of subclinical pulmonary perfusion abnormalities that could herald the development of significant lung disease in these susceptible individuals.
Kohli P, Kelly VJ, Hibbert KA, Corleis B, Kone M, Cho JL, Defaria-Yeh D, Kwon DS, Medoff BD, Harris RS, Winkler T.
The cervicovaginal mucus barrier to HIV-1 is diminished in bacterial vaginosis - PLoS Pathogens - 2020
Bacterial vaginosis (BV), a condition in which the vaginal microbiota consists of community of obligate and facultative anaerobes rather than dominated by a single species of Lactobacillus, affects ~30% of women in the US. Women with BV are at 60% increased risk for HIV acquisition and are 3-times more likely to transmit HIV to an uninfected partner. As cervicovaginal mucus (CVM) is the first line of defense against mucosal pathogens and the home of the resident vaginal microbiota, we hypothesized the barrier function of CVM to HIV may be diminished in BV. Here, we characterized CVM properties including pH, lactic acid content, and Nugent score to correlate with the microbiota community composition, which was confirmed by 16S rDNA sequencing on a subset of samples. We then quantified the mobility of fluorescently-labeled HIV virions and nanoparticles to characterize the structural and adhesive barrier properties of CVM. Our analyses included women with Nugent scores categorized as intermediate (4-6) and BV (7-10), women that were either symptomatic or asymptomatic, and a small group of women before and after antibiotic treatment for symptomatic BV. Overall, we found that HIV virions had significantly increased mobility in CVM from women with BV compared to CVM from women with Lactobacillus crispatus-dominant microbiota, regardless of whether symptoms were present. We confirmed using nanoparticles and scanning electron microscopy that the impaired barrier function was due to reduced adhesive barrier properties without an obvious degradation of the physical CVM pore structure. We further confirmed a similar increase in HIV mobility in CVM from women with Lactobacillus iners-dominant microbiota, the species most associated with transitions to BV and that persists after antibiotic treatment for BV. Our findings advance the understanding of the protective role of mucus and highlight the interplay between vaginal microbiota and the innate barrier function mucus.
The Evolving Facets of Bacterial Vaginosis: Implications for HIV Transmission - AIDS Res Hum Retroviruses - 2019
Bacterial vaginosis (BV) is a common yet poorly understood vaginal condition that has become a major focus of HIV transmission and immunology research. Varied terminologies are used by clinicians and researchers to describe microbial communities that reside in the female reproductive tract (FRT), which is driven, in part, by microbial genetic and metabolic complexity, evolving diagnostic and molecular techniques, and multidisciplinary perspectives of clinicians, epidemiologists, microbiologists, and immunologists who all appreciate the scientific importance of understanding mechanisms that underlie BV. This Perspectives article aims to clarify the varied terms used to describe the cervicovaginal microbiota and its “nonoptimal” state, under the overarching term of BV. The ultimate goal is to move toward language standardization in future literature that facilitates a better understanding of the impact of BV on FRT immunology and risk of sexually transmitted infections, including HIV.
Lyle R. McKinnon, Sharon L. Achilles, Catriona S. Bradshaw, Adam Burgener, Tania Crucitti, David N.Fredricks, Heather B. Jaspan, Rupert Kaul, Charu Kaushic, Nichole Klatt, Douglas S. Kwon, Jeanne M. Marrazzo, Lindi Masson, R. Scott McClelland, Jacques Ravel, Janneke H. H. M. van de Wijgert, Lenka A. Vodstrcil, Gilda Tachedjian
HIV-1 and SIV Infection Are Associated with Early Loss of Lung Interstitial CD4+ T Cells and Dissemination of Pulmonary Tuberculosis - Cell Reports - 2019
Lung interstitial CD4+ T cells are critical for protection against pulmonary infections, but the fate of this population during HIV-1 infection is not well described. We studied CD4+ T cells in the setting of HIV-1 infection in human lung tissue, humanized mice, and a Mycobacterium tuberculosis (Mtb)/simian immunodeficiency virus (SIV) nonhuman primate co-infection model. Infection with a CCR5-tropic strain of HIV-1 or SIV results in severe and rapid loss of lung interstitial CD4+ T cells but not blood or lung alveolar CD4+ T cells. This is accompanied by high HIV-1 production in these cells in vitro and in vivo. Importantly, during early SIV infection, loss of lung interstitial CD4+ T cells is associated with increased dissemination of pulmonary Mtb infection. We show that lung interstitial CD4+ T cells serve as an efficient target for HIV-1 and SIV infection that leads to their early depletion and an increased risk of disseminated tuberculosis.
HIV-1 and SIV Infection Are Associated with Early Loss of Lung Interstitial CD4+ T Cells and Dissemination of Pulmonary Tuberculosis.
Corleis B, Bucsan AN, Deruaz M, Vrbanac VD, Lisanti-Park AC, Gates SJ, Linder AH, Paer JM, Olson GS, Bowman BA, Schiff AE, Medoff BD, Tager AM, Luster AD, Khader SA, Kaushal D, Kwon DS. Cell reports. 2019; 26(6):1409-1418.e5.
Brief Report: Systemic Inflammation, Immune Activation, and Impaired Lung Function Among People Living With HIV in Rural Uganda - Journal of Acquired Immune Deficiency Syndromes - 2018
Although both chronic lung disease and HIV are inflammatory diseases common in sub-Saharan Africa, the relationship between systemic inflammation and lung function among people living with HIV (PLWH) in sub-Saharan Africa is not well described.
We measured lung function (using spirometry) and serum high sensitivity C-reactive protein, interleukin 6 (IL-6), soluble CD14 (sCD14), and soluble CD163 (sCD163) in 125 PLWH on stable antiretroviral therapy (ART) and 109 age- and sex-similar HIV-uninfected control subjects in rural Uganda. We modeled the relationship between lung function and systemic inflammation using linear regression, stratified by HIV serostatus, controlled for age, sex, height, tobacco, and biomass exposure.
Half of subjects [46% (107/234)] were women, and the median age was 52 years (interquartile range: 48-55). Most PLWH [92% (115/125)] were virologically suppressed on first-line ART. Median CD4 count was 472 cells/mm. In multivariable linear regression models stratified by HIV serostatus, an interquartile range increase in IL-6 and sCD163 were each inversely associated with lung function (mL, 95% confidence interval) among PLWH [IL-6: forced expiratory volume in 1 second (FEV1) -18.1 (-29.1 to -7.1), forced vital capacity (FVC) -17.1 (-28.2 to -5.9); sCD163: FVC -14.3 (-26.9 to -1.7)]. High sensitivity C-reactive protein (>3 vs. <1 mg/L) was inversely associated with lung function among both PLWH and HIV-uninfected control subjects [PLWH: FEV1 -39.3 (-61.7 to -16.9), FVC -44.0 (-48.4 to -6.4); HIV-uninfected: FEV1 -37.9 (-63.2 to -12.6), FVC -58.0 (-88.4 to -27.5)]. sCD14 was not associated with lung function, and all interaction terms were insignificant.
Macrophage activation and systemic inflammation are associated with lower lung function among PLWH on stable ART in rural Uganda. Future work should focus on underlying mechanisms and public health implications.
Brief Report: Systemic Inflammation, Immune Activation, and Impaired Lung Function Among People Living With HIV in Rural Uganda.
North CM, Muyanja D, Kakuhikire B, Tsai AC, Tracy RP, Hunt PW, Kwon DS, Christiani DC, Okello S, Siedner MJ. Journal of acquired immune deficiency syndromes (1999). 2018; 78(5):543-548. NIHMSID: NIHMS960217
Increased Systemic Inflammation and Gut Permeability Among Women with Treated HIV Infection in Rural Uganda - The Journal of Infectious Disease - 2018
In a cohort of HIV-infected individuals and age and sex-matched HIV-uninfected comparators, we assessed soluble (s)CD14, sCD163, interleukin (IL)-6, intestinal fatty acid binding protein (IFAPB) and high-sensitivity C-reactive protein (hs-CRP). The median age was 51 years; and among HIV+, median ART duration was 7 years, median CD4 T-cell count was 433, and 86% had an undetectable viral load. Although HIV+ had higher sCD14, IFABP and hs-CRP, we found evidence of interaction by sex, such that HIV+ women had greater differences versus HIV- compared to men. In models restricted to HIV+, women had higher levels of all five biomarkers than men.
Siedner MJ, Zanni M, Tracy RP, Kwon DS, Tsai AC, Kakuhire B, Hunt PW, Okello S. The Journal of infectious diseases. 2018
Introduction: Physician-Scientists in the Evolving Landscape of Biomedical Research – The Journal of Infectious Diseases – 2018
The seed of this supplement was a physician-scientist symposium held in April 2017, cosponsored by the Ragon Institute and the Harvard University Center for AIDS Research. The goals of the symposium were to highlight excellent work by physician-scientists from around the country, to explore the variety of ways in which clinical training influence research, and to develop ideas of how to more completely support the careers of physician-scientists. To achieve these goals, we asked Catherine Blish, MD, PhD (Stanford University, Stanford, CA), Victor Nizet, MD (University of California–San Diego), Michael Glickman, MD (Memorial Sloan Kettering Cancer Center, New York, NY), Ramnik Xavier, MD (Massachusetts General Hospital,…
Introduction: Physician-Scientists in the Evolving Landscape of Biomedical Research.
The Journal of Infectious Diseases, Volume 218, Issue suppl_1, 15 September 2018, Pages S1–S2
Cervicovaginal Microbiota and Reproductive Health: The Virtue of Simplicity - Cell Host & Microbe - 2018
Cervicovaginal microbiota play a critical role in women’s health and reproductive outcomes. Despite being one of the simplest commensal bacterial communities in the human body, we are only beginning to appreciate its complex dynamic nature and important role in host immune modulation. In this review, we discuss the “optimal” cervicovaginal bacterial community composition, the impact of microbiota on gynecologic and obstetric outcomes, and the hurdles to developing a deeper mechanistic understanding of the function of the cervicovaginal microbiome. We then describe efforts to durably alter microbial composition in this compartment by promotion of Lactobacillus colonization with probiotics, modulation of vaginal pH, hormonal administration, and the eradication of pathogenic bacteria with antibiotics. Finally, we draw on lessons learned from the deeply investigated gut microbiome to suggest future avenues of research into host-pathogen interactions in the female genital tract.
Cervicovaginal Microbiota and Reproductive Health: The Virtue of Simplicity
Anahtar M, Gootenberg D, Mitchell C, Kwon DS. Cell Host & Microbe, Volume 23, Issue 2 , 159–168.
Gut microbiota is critical for the induction of chemotherapy-induced pain - Nature Neuroscience - 2017
Chemotherapy-induced pain is a dose-limiting condition that affects 30% of patients undergoing chemotherapy. We found that gut microbiota promotes the development of chemotherapy-induced mechanical hyperalgesia. Oxaliplatin-induced mechanical hyperalgesia was reduced in germ-free mice and in mice pretreated with antibiotics. Restoring the microbiota of germ-free mice abrogated this protection. These effects appear to be mediated, in part, by TLR4 expressed on hematopoietic cells, including macrophages.
Next-generation Sequencing of the DNA Virome from Fecal Samples - Bio-Protocol - 2017
Herein we describe a detailed protocol for DNA virome analysis of low input human stool samples (Monaco et al., 2016). This protocol is divided into four main steps: 1) stool samples are pulverized to evenly distribute microbial matter; 2) stool is enriched for virus-like particles and DNA is extracted by phenol-chloroform; 3) purified DNA is multiple-strand displacement amplified (MDA) and fragmented; and 4) libraries are constructed and sequenced using Illumina Miseq. Subsequent sequence analysis for viral sequence identification should be sensitive but stringent.
Next-generation Sequencing of the DNA Virome from Fecal Samples.
Monaco CL, Kwon DS. Bio-protocol. 2017; 7(5). NIHMSID: NIHMS873168
HIV-associated changes in the enteric microbial community: potential role in loss of homeostasis and development of systemic inflammation - Current Opinion in Infectious Disease - 2017
PURPOSE OF REVIEW:
Despite HIV therapy advances, average life expectancy in HIV-infected individuals on effective treatment is significantly decreased relative to uninfected persons, largely because of increased incidence of inflammation-related diseases, such as cardiovascular disease and renal dysfunction. The enteric microbial community could potentially cause this inflammation, as HIV-driven destruction of gastrointestinal CD4 T cells may disturb the microbiota-mucosal immune system balance, disrupting the stable gut microbiome and leading to further deleterious host outcomes.
Varied enteric microbiome changes have been reported during HIV infection, but unifying patterns have emerged. Community diversity is decreased, similar to pathologies such as inflammatory bowel disease, obesity, and Clostridium difficile infection. Many taxa frequently enriched in HIV-infected individuals, such as Enterobacteriaceae and Erysipelotrichaceae, have pathogenic potential, whereas depleted taxa, such as Bacteroidaceae and Ruminococcaceae, are more linked with anti-inflammatory properties and maintenance of gut homeostasis. The gut viral community in HIV has been found to contain a greater abundance of pathogenesis-associated Adenoviridae and Anelloviridae. These bacterial and viral changes correlate with increased systemic inflammatory markers, such as serum sCD14, sCD163, and IL-6.
Enteric microbial community changes may contribute to chronic HIV pathogenesis, but more investigation is necessary, especially in the developing world population with the greatest HIV burden (Video, Supplemental Digital Content 1, http://links.lww.com/COID/A15, which includes the authors’ summary of the importance of the work).
HIV-associated changes in the enteric microbial community: potential role in loss of homeostasis and development of systemic inflammation.
Gootenberg DB, Paer JM, Luevano JM, Kwon DS. Current opinion in infectious diseases. 2017; 30(1):31-43.
Lactobacillus-Deficient Cervicovaginal Bacterial Communities Are Associated with Increased HIV Acquisition in Young South African Women - Immunity - 2017
Elevated inflammation in the female genital tract is associated with increased HIV risk. Cervicovaginal bacteria modulate genital inflammation; however, their role in HIV susceptibility has not been elucidated. In a prospective cohort of young, healthy South African women, we found that individuals with diverse genital bacterial communities dominated by anaerobes other than Gardnerella were at over 4-fold higher risk of acquiring HIV and had increased numbers of activated mucosal CD4+ T cells compared to those with Lactobacillus crispatus-dominant communities. We identified specific bacterial taxa linked with reduced (L. crispatus) or elevated (Prevotella, Sneathia, and other anaerobes) inflammation and HIV infection and found that high-risk bacteria increased numbers of activated genital CD4+ T cells in a murine model. Our results suggest that highly prevalent genital bacteria increase HIV risk by inducing mucosal HIV target cells. These findings might be leveraged to reduce HIV acquisition in women living in sub-Saharan Africa.
Lactobacillus-Deficient Cervicovaginal Bacterial Communities Are Associated with Increased HIV Acquisition in Young South African Women.
Gosmann C, Anahtar MN, Handley SA, Farcasanu M, Abu-Ali G, Bowman BA, Padavattan N, Desai C, Droit L, Moodley A, Dong M, Chen Y, Ismail N, Ndung’u T, Ghebremichael MS, Wesemann DR, Mitchell C, Dong KL, Huttenhower C, Walker BD, Virgin HW, Kwon DS. Immunity. 2017; 46(1):29-37. NIHMSID: NIHMS840381
Fc receptor-mediated phagocytosis in tissues as a potent mechanism for preventive and therapeutic HIV vaccine strategies - Mucosal Immunology - 2016
Although the development of a fully protective HIV vaccine is the ultimate goal of HIV research, to date only one HIV vaccine trial, the RV144, has successfully induced a weakly protective response. The 31% protection from infection achieved in the RV144 trial was linked to the induction of nonneutralizing antibodies, able to mediate antibody-dependent cell-mediated cytotoxicity (ADCC), suggestive of an important role of Fc-mediated functions in protection. Similarly, Fc-mediated antiviral activity was recently shown to play a critical role in actively suppressing the viral reservoir, but the Fc effector mechanisms within tissues that provide protection from or after infection are largely unknown. Here we aimed to define the landscape of effector cells and Fc receptors present within vulnerable tissues. We found negligible Fc receptor-expressing natural killer cells in the female reproductive and gastrointestinal mucosa. Conversely, Fc receptor-expressing macrophages were highly enriched in most tissues, but neutrophils mediated superior antibody-mediated phagocytosis. Modifications in Fc domain of VRC01 antibody increased phagocytic responses in both phagocytes. These data suggest that non-ADCC-mediated mechanisms, such as phagocytosis and neutrophil activation, are more likely to play a role in preventative vaccine or reservoir-eliminating therapeutic approaches.
Fc receptor-mediated phagocytosis in tissues as a potent mechanism for preventive and therapeutic HIV vaccine strategies.
Sips M, Krykbaeva M, Diefenbach TJ, Ghebremichael M, Bowman BA, Dugast AS, Boesch AW, Streeck H, Kwon DS, Ackerman ME, Suscovich TJ, Brouckaert P, Schacker TW, Alter G. Mucosal immunology. 2016; 9(6):1584-1595. NIHMSID: NIHMS753586
Efficient Nucleic Acid Extraction and 16S rRNA Gene Sequencing for Bacterial Community Characterization - Journal of Visualized Experiments - 2016
There is a growing appreciation for the role of microbial communities as critical modulators of human health and disease. High throughput sequencing technologies have allowed for the rapid and efficient characterization of bacterial communities using 16S rRNA gene sequencing from a variety of sources. Although readily available tools for 16S rRNA sequence analysis have standardized computational workflows, sample processing for DNA extraction remains a continued source of variability across studies. Here we describe an efficient, robust, and cost effective method for extracting nucleic acid from swabs. We also delineate downstream methods for 16S rRNA gene sequencing, including generation of sequencing libraries, data quality control, and sequence analysis. The workflow can accommodate multiple samples types, including stool and swabs collected from a variety of anatomical locations and host species. Additionally, recovered DNA and RNA can be separated and used for other applications, including whole genome sequencing or RNA-seq. The method described allows for a common processing approach for multiple sample types and accommodates downstream analysis of genomic, metagenomic and transcriptional information.
Efficient Nucleic Acid Extraction and 16S rRNA Gene Sequencing for Bacterial Community Characterization.
Anahtar MN, Bowman BA, Kwon DS. Journal of visualized experiments: JoVE. 2016; (110).
Association between injectable progestin-only contraceptives and HIV acquisition and HIV target cell frequency in the female genital tract in South African women: a prospective cohort study - The Lancet - 2016
The use of injectable progestin-only contraceptives has been associated with increased risk of HIV acquisition in observational studies, but the biological mechanisms of this risk remain poorly understood. We aimed to assess the effects of progestins on HIV acquisition risk and the immune environment in the female genital tract.
In this prospective cohort, we enrolled HIV-negative South African women aged 18-23 years who were not pregnant and were living in Umlazi, South Africa from the Females Rising through Education, Support, and Health (FRESH) study. We tested for HIV-1 twice per week to monitor incident infection. Every 3 months, we collected demographic and behavioural data in addition to blood and cervical samples. The study objective was to characterise host immune determinants of HIV acquisition risk, including those associated with injectable progestin-only contraceptive use. Hazard ratios (HRs) were estimated using Cox proportional hazards methods.
Between Nov 19, 2012, and May 31, 2015, we characterised 432 HIV-uninfected South African women from the FRESH study. In this cohort, 152 women used injectable progestin-only contraceptives, 43 used other forms of contraception, and 222 women used no method of long-term contraception. Women using injectable progestin-only contraceptives were at substantially higher risk of acquiring HIV (12·06 per 100 person-years, 95% CI 6·41-20·63) than women using no long-term contraception (3·71 per 100 person-years, 1·36-8·07; adjusted hazard ratio [aHR] 2·93, 95% CI 1·09-7·868, p=0·0326). HIV-negative injectable progestin-only contraceptive users had 3·92 times the frequency of cervical HIV target cells (CCR5+ CD4 T cells) compared with women using no long-term contraceptive (p=0·0241). Women using no long-term contraceptive in the luteal phase of the menstrual cycle also had a 3·25 times higher frequency of cervical target cells compared with those in the follicular phase (p=0·0488), suggesting that a naturally high progestin state had similar immunological effects to injectable progestin-only contraceptives.
Injectable progestin-only contraceptive use and high endogenous progesterone are both associated with increased frequency of activated HIV targets cells at the cervix, the site of initial HIV entry in most women, providing a possible biological mechanism underlying increased HIV acquisition in women with high progestin exposure.
The Bill and Melinda Gates Foundation and the National Institute of Allergy and Infectious Diseases.
Association between injectable progestin-only contraceptives and HIV acquisition and HIV target cell frequency in the female genital tract in South African women: a prospective cohort study.
Byrne EH, Anahtar MN, Cohen KE, Moodley A, Padavattan N, Ismail N, Bowman BA, Olson GS, Mabhula A, Leslie A, Ndung’u T, Walker BD, Ghebremichael MS, Dong KL, Kwon DS. The Lancet. Infectious diseases. 2016; 16(4):441-8. NIHMSID: NIHMS844271
HIV Skews the Lineage-Defining Transcriptional Profile of Mycobacterium tuberculosis-Specific CD4+ T Cells - Journal of Immunology - 2016
HIV-infected persons are at greater risk of developing tuberculosis (TB) even before profound CD4 loss occurs, suggesting that HIV alters CD4(+) T cell functions capable of containing bacterial replication. An effective immune response to Mycobacterium tuberculosis most likely relies on the development of a balanced CD4 response, in which distinct CD4(+) Th subsets act in synergy to control the infection. To define the diversity of M. tuberculosis-specific CD4(+) Th subsets and determine whether HIV infection impacts such responses, the expression of lineage-defining transcription factors T-bet, Gata3, RORγt, and Foxp3 was measured in M. tuberculosis-specific CD4(+) T cells in HIV-uninfected (n = 20) and HIV-infected individuals (n = 20) with latent TB infection. Our results show that, upon 5-d restimulation in vitro, M. tuberculosis-specific CD4(+) T cells from healthy individuals have the ability to exhibit a broad spectrum of Th subsets, defined by specific patterns of transcription factor coexpression. These transcription factor profiles were skewed in HIV-infected individuals where the proportion of T-bet(high)Foxp3(+) M. tuberculosis-specific CD4(+) T cells was significantly decreased (p = 0.002) compared with HIV-uninfected individuals, a change that correlated inversely with HIV viral load (p = 0.0007) and plasma TNF-α (p = 0.027). Our data demonstrate an important balance in Th subset diversity defined by lineage-defining transcription factor coexpression profiles that is disrupted by HIV infection and suggest a role for HIV in impairing TB immunity by altering the equilibrium of M. tuberculosis-specific CD4(+) Th subsets.
HIV Skews the Lineage-Defining Transcriptional Profile of Mycobacterium tuberculosis-Specific CD4+ T Cells.
Riou C, Strickland N, Soares AP, Corleis B, Kwon DS, Wherry EJ, Wilkinson RJ, Burgers WA.
Journal of immunology (Baltimore, Md.: 1950). 2016; 196(7):3006-18. NIHMSID: NIHMS756711
Altered Virome and Bacterial Microbiome in Human Immunodeficiency Virus-Associated Acquired Immunodeficiency Syndrome - Cell Host & Microbe - 2016
Human immunodeficiency virus (HIV) infection is associated with increased intestinal translocation of microbial products and enteropathy as well as alterations in gut bacterial communities. However, whether the enteric virome contributes to this infection and resulting immunodeficiency remains unknown. We characterized the enteric virome and bacterial microbiome in a cohort of Ugandan patients, including HIV-uninfected or HIV-infected subjects and those either treated with anti-retroviral therapy (ART) or untreated. Low peripheral CD4 T cell counts were associated with an expansion of enteric adenovirus sequences and this increase was independent of ART treatment. Additionally, the enteric bacterial microbiome of patients with lower CD4 T counts exhibited reduced phylogenetic diversity and richness with specific bacteria showing differential abundance, including increases in Enterobacteriaceae, which have been associated with inflammation. Thus, immunodeficiency in progressive HIV infection is associated with alterations in the enteric virome and bacterial microbiome, which may contribute to AIDS-associated enteropathy and disease progression.
Altered Virome and Bacterial Microbiome in Human Immunodeficiency Virus-Associated Acquired Immunodeficiency Syndrome.
Monaco CL, Gootenberg DB, Zhao G, Handley SA, Ghebremichael MS, Lim ES, Lankowski A, Baldridge MT, Wilen CB, Flagg M, Norman JM, Keller BC, Luévano JM, Wang D, Boum Y, Martin JN, Hunt PW, Bangsberg DR, Siedner MJ, Kwon DS, Virgin HW. Cell host & microbe. 2016; 19(3):311-22. NIHMSID: NIHMS764192
SIV Infection-Mediated Changes in Gastrointestinal Bacterial Microbiome and Virome Are Associated with Immunodeficiency and Prevented by Vaccination - Cell Host & Microbe - 2016
AIDS caused by simian immunodeficiency virus (SIV) infection is associated with gastrointestinal disease, systemic immune activation, and, in cross-sectional studies, changes in the enteric virome. Here we performed a longitudinal study of a vaccine cohort to define the natural history of changes in the fecal metagenome in SIV-infected monkeys. Matched rhesus macaques were either uninfected or intrarectally challenged with SIV, with a subset receiving the Ad26 vaccine, an adenovirus vector expressing the viral Env/Gag/Pol antigens. Progression of SIV infection to AIDS was associated with increased detection of potentially pathogenic viruses and bacterial enteropathogens. Specifically, adenoviruses were associated with an increased incidence of gastrointestinal disease and AIDS-related mortality. Viral and bacterial enteropathogens were largely absent from animals protected by the vaccine. These data suggest that the SIV-associated gastrointestinal disease is associated with the presence of both viral and bacterial enteropathogens and that protection against SIV infection by vaccination prevents enteropathogen emergence.
SIV Infection-Mediated Changes in Gastrointestinal Bacterial Microbiome and Virome Are Associated with Immunodeficiency and Prevented by Vaccination.
Handley SA, Desai C, Zhao G, Droit L, Monaco CL, Schroeder AC, Nkolola JP, Norman ME, Miller AD, Wang D, Barouch DH, Virgin HW.
Cell host & microbe. 2016; 19(3):323-35. NIHMSID: NIHMS764191
Immunization of HIV-1-Infected Persons With Autologous Dendritic Cells Transfected With mRNA Encoding HIV-1 Gag and Nef: Results of a Randomized, Placebo-Controlled Clinical Trial - Journal of Acquired Immune Deficiency Syndromes - 2016
HIV-1 eradication may require reactivation of latent virus along with stimulation of HIV-1-specific immune responses to clear infected cells. Immunization with autologous dendritic cells (DCs) transfected with viral mRNA is a promising strategy for eliciting HIV-1-specific immune responses. We performed a randomized controlled clinical trial to evaluate the immunogenicity of this approach in HIV-1-infected persons on antiretroviral therapy.
Fifteen participants were randomized 2:1 to receive intradermal immunization with HIV-1 Gag- and Nef-transfected DCs (vaccine) or mock-transfected DCs (placebo) at weeks 0, 2, 6, and 10. All participants also received DCs pulsed with keyhole limpet hemocyanin (KLH) to assess whether responses to a neo-antigen could be induced.
After immunization, there were no differences in interferon-gamma enzyme-linked immunospot responses to HIV-1 Gag or Nef in the vaccine or placebo group. CD4 proliferative responses to KLH increased 2.4-fold (P = 0.026) and CD8 proliferative responses to KLH increased 2.5-fold (P = 0.053) after vaccination. There were increases in CD4 proliferative responses to HIV-1 Gag (2.5-fold vs. baseline, 3.4-fold vs. placebo, P = 0.054) and HIV-1 Nef (2.3-fold vs. baseline, 6.3-fold vs. placebo, P = 0.009) among vaccine recipients, but these responses were short-lived.
Immunization with DCs transfected with mRNA encoding HIV-1 Gag and Nef did not induce significant interferon-gamma enzyme-linked immunospot responses. There were increases in proliferative responses to HIV-1 antigens and to a neo-antigen, KLH, but the effects were transient. Dendritic cell vaccination should be optimized to elicit stronger and long-lasting immune responses for this strategy to be effective as an HIV-1 therapeutic vaccine.
Immunization of HIV-1-Infected Persons With Autologous Dendritic Cells Transfected With mRNA Encoding HIV-1 Gag and Nef: Results of a Randomized, Placebo-Controlled Clinical Trial.
Gandhi RT, Kwon DS, Macklin EA, Shopis JR, McLean AP, McBrine N, Flynn T, Peter L, Sbrolla A, Kaufmann DE, Porichis F, Walker BD, Bhardwaj N, Barouch DH, Kavanagh DG. Journal of acquired immune deficiency syndromes (1999). 2016; 71(3):246-53. NIHMSID: NIHMS721414
HIV infection and arterial stiffness among older-adults taking antiretroviral therapy in rural Uganda - AIDS - 2016
HIV infection is associated with arterial stiffness, but no studies have assessed this relationship in sub-Saharan Africa. We enrolled 205 participants over 40 years old in Uganda: 105 on antiretroviral therapy for a median of 7 years, and a random sample of 100 age and sex-matched HIV-uninfected controls from the clinic catchment area. The prevalence of arterial stiffness (ankle brachial index > 1.2) was 33%, 18%, 19% and 2% in HIV+ men, HIV- men, HIV+ women, and HIV- women. In multivariable models adjusted for cardiovascular risk factors, HIV+ individuals had over double the prevalence of arterial stiffness (adjusted prevalence ratio 2.86, 95% confidence interval 1.41-5.79, P = 0.003).
HIV infection and arterial stiffness among older-adults taking antiretroviral therapy in rural Uganda.
Siedner MJ, Kim JH, Nakku RS, Hemphill L, Triant VA, Haberer JE, Martin JN, Boum Y 2nd, Kwon DS, Tsai AC, Hunt PW, Okello S, Bangsberg DR. AIDS (London, England). 2016; 30(4):667-70. NIHMSID: NIHMS744423
Persistent Immune Activation and Carotid Atherosclerosis in HIV-Infected Ugandans Receiving Antiretroviral Therapy - The Journal of Infectious Disease - 2016
Human immunodeficiency virus (HIV) infection and associated immune activation predict the risk of cardiovascular disease in resource-rich areas. Less is known about these relationships in sub-Saharan Africa.
Beginning in 2005, we enrolled subjects in southwestern Uganda into a cohort at the time of antiretroviral therapy (ART) initiation. Multiple immune activation measures were assessed before and 6 months after ART initiation. Beginning in 2013, participants aged >40 years underwent metabolic profiling, including measurement of hemoglobin A1c and lipid levels and carotid ultrasonography. We fit regression models to identify traditional and HIV-specific correlates of common carotid intima media thickness (CCIMT).
A total of 105 participants completed carotid ultrasonography, with a median completion time of 7 years following ART initiation. Age, low-density lipoprotein cholesterol level, and pre-ART HIV load were correlated with CCIMT. No association was found between CCIMT and any pre-ART biomarkers of immune activation. However, in multivariable models adjusted for cardiovascular disease risk factors, lower absolute levels of soluble CD14 and interleukin 6 and greater declines in the CD14 level and kynurenine-tryptophan ratio after 6 months of ART predicted a lower CCIMT years later (P < .01).
Persistent immune activation despite ART-mediated viral suppression predicts the future atherosclerotic burden among HIV-infected Ugandans. Future work should focus on clinical correlates of these relationships, to elucidate the long-term health priorities for HIV-infected people in the region.
Persistent Immune Activation and Carotid Atherosclerosis in HIV-Infected Ugandans Receiving Antiretroviral Therapy.
Siedner MJ, Kim JH, Nakku RS, Bibangambah P, Hemphill L, Triant VA, Haberer JE, Martin JN, Mocello AR, Boum Y 2nd, Kwon DS, Tracy RP, Burdo T, Huang Y, Cao H, Okello S, Bangsberg DR, Hunt PW. The Journal of infectious diseases. 2016; 213(3):370-8.
Viral immunity. Transkingdom control of viral infection and immunity in the mammalian intestine - Science - 2016
Viruses that infect the intestine include major human pathogens (retroviruses, noroviruses, rotaviruses, astroviruses, picornaviruses, adenoviruses, herpesviruses) that constitute a serious public health problem worldwide. These viral pathogens are members of a large, complex viral community inhabiting the intestine termed “the enteric virome.” Enteric viruses have intimate functional and genetic relationships with both the host and other microbial constituents that inhabit the intestine, such as the bacterial microbiota, their associated phages, helminthes, and fungi, which together constitute the microbiome. Emerging data indicate that enteric viruses regulate, and are in turn regulated by, these other microbes through a series of processes termed “transkingdom interactions.” This represents a changing paradigm in intestinal immunity to viral infection. Here we review recent advances in the field and propose new ways in which to conceptualize this important area.
Viral immunity. Transkingdom control of viral infection and immunity in the mammalian intestine.
Pfeiffer JK, Virgin HW.
Science (New York, N.Y.). 2016; 351(6270). NIHMSID: NIHMS757312
IL-21 induces antiviral microRNA-29 in CD4 T cells to limit HIV-1 infection - Nature - 2016
Initial events after exposure determine HIV-1 disease progression, underscoring a critical need to understand host mechanisms that interfere with initial viral replication. Although associated with chronic HIV-1 control, it is not known whether interleukin-21 (IL-21) contributes to early HIV-1 immunity. Here we take advantage of tractable primary human lymphoid organ aggregate cultures to show that IL-21 directly suppresses HIV-1 replication, and identify microRNA-29 (miR-29) as an antiviral factor induced by IL-21 in CD4 T cells. IL-21 promotes transcription of all miR-29 species through STAT3, whose binding to putative regulatory regions within the MIR29 gene is enriched by IL-21 signalling. Notably, exogenous IL-21 limits early HIV-1 infection in humanized mice, and lower viremia in vivo is associated with higher miR-29 expression. Together, these findings reveal a novel antiviral IL-21-miR-29 axis that promotes CD4 T-cell-intrinsic resistance to HIV-1 infection, and suggest a role for IL-21 in initial HIV-1 control in vivo.
IL-21 induces antiviral microRNA-29 in CD4 T cells to limit HIV-1 infection.
Adoro S, Cubillos-Ruiz JR, Chen X, Deruaz M, Vrbanac VD, Song M, Park S, Murooka TT, Dudek TE, Luster AD, Tager AM, Streeck H, Bowman B, Walker BD, Kwon DS, Lazarevic V, Glimcher LH.
Nature communications. 2015; 6:7562. NIHMSID: NIHMS693385
Cervicovaginal bacteria are a major modulator of host inflammatory responses in the female genital tract - Immunity - 2015
Colonization by Lactobacillus in the female genital tract is thought to be critical for maintaining genital health. However, little is known about how genital microbiota influence host immune function and modulate disease susceptibility. We studied a cohort of asymptomatic young South African women and found that the majority of participants had genital communities with low Lactobacillus abundance and high ecological diversity. High-diversity communities strongly correlated with genital pro-inflammatory cytokine concentrations in both cross-sectional and longitudinal analyses. Transcriptional profiling suggested that genital antigen-presenting cells sense gram-negative bacterial products in situ via Toll-like receptor 4 signaling, contributing to genital inflammation through activation of the NF-κB signaling pathway and recruitment of lymphocytes by chemokine production. Our study proposes a mechanism by which cervicovaginal microbiota impact genital inflammation and thereby might affect a woman’s reproductive health, including her risk of acquiring HIV.
Cervicovaginal bacteria are a major modulator of host inflammatory responses in the female genital tract.
Anahtar MN, Byrne EH, Doherty KE, Bowman BA, Yamamoto HS, Soumillon M, Padavattan N, Ismail N, Moodley A, Sabatini ME, Ghebremichael MS, Nusbaum C, Huttenhower C, Virgin HW, Ndung’u T, Dong KL, Walker BD, Fichorova RN, Kwon DS.
Immunity. 2015; 42(5):965-76. NIHMSID: NIHMS689549
Vertically transmitted faecal IgA levels determine extra-chromosomal phenotypic variation - Nature - 2015
The proliferation of genetically modified mouse models has exposed phenotypic variation between investigators and institutions that has been challenging to control. In many cases, the microbiota is the presumed cause of the variation. Current solutions to account for phenotypic variability include littermate and maternal controls or defined microbial consortia in gnotobiotic mice. In conventionally raised mice, the microbiome is transmitted from the dam. Here we show that microbially driven dichotomous faecal immunoglobulin-A (IgA) levels in wild-type mice within the same facility mimic the effects of chromosomal mutations. We observe in multiple facilities that vertically transmissible bacteria in IgA-low mice dominantly lower faecal IgA levels in IgA-high mice after co-housing or faecal transplantation. In response to injury, IgA-low mice show increased damage that is transferable by faecal transplantation and driven by faecal IgA differences. We find that bacteria from IgA-low mice degrade the secretory component of secretory IgA as well as IgA itself. These data indicate that phenotypic comparisons between mice must take into account the non-chromosomal hereditary variation between different breeders. We propose faecal IgA as one marker of microbial variability and conclude that co-housing and/or faecal transplantation enables analysis of progeny from different dams.
Vertically transmitted faecal IgA levels determine extra-chromosomal phenotypic variation.
Moon C, Baldridge MT, Wallace MA, D CA, Burnham, Virgin HW, Stappenbeck TS.
Nature. 2015; 521(7550):90-93. NIHMSID: NIHMS646815
Profiling human antibody responses by integrated single-cell analysis - Vaccine - 2014
Comprehensive characterization of the antigen-specific B cells induced during infections or following vaccination would facilitate the discovery of novel antibodies and inform how interventions shape protective humoral responses. The analysis of human B cells and their antibodies has been performed using flow cytometry to evaluate memory B cells and expanded plasmablasts, while microtechnologies have also provided a useful tool to examine plasmablasts/plasma cells after vaccination. Here we present an integrated analytical platform, using arrays of subnanoliter wells (nanowells), for constructing detailed profiles for human B cells comprising the immunophenotypes of these cells, the distribution of isotypes of the secreted antibodies, the specificity and relative affinity for defined antigens, and for a subset of cells, the genes encoding the heavy and light chains. The approach combines on-chip image cytometry, microengraving, and single-cell RT-PCR. Using clinical samples from HIV-infected subjects, we demonstrate that the method can identify antigen-specific neutralizing antibodies, is compatible with both plasmablasts/plasma cells and activated memory B cells, and is well-suited for characterizing the limited numbers of B cells isolated from tissue biopsies (e.g., colon biopsies). The technology should facilitate detailed analyses of human humoral responses for evaluating vaccines and their ability to raise protective antibody responses across multiple anatomical compartments.
Profiling human antibody responses by integrated single-cell analysis.
Ogunniyi AO, Thomas BA, Politano TJ, Varadarajan N, Landais E, Poignard P, Walker BD, Kwon DS, Love JC.
Vaccine. 2014; 32(24):2866-73. NIHMSID: NIHMS571557
Differential impact of PD-1 and/or interleukin-10 blockade on HIV-1-specific CD4 T cell and antigen-presenting cell functions - Journal of Virology - 2014
Antigen persistence in chronic infections and cancer upregulates inhibitory networks, such as the PD-1 and interleukin-10 (IL-10) pathways, that impair immunity and lead to disease progression. These pathways are attractive targets for immunotherapy, as demonstrated by recent clinical trials of PD-1/PD-L1 blockade in cancer patients. However, in HIV-1 infection not all subjects respond to inhibition of either pathway and the mechanistic interactions between these two networks remain to be better defined. Here we demonstrate that in vitro blockade of PD-L1 and/or IL-10Rα results in markedly different profiles of HIV-1-specific CD4 T cell restoration. Whereas PD-L1 blockade leads to balanced increase in gamma interferon (IFN-γ), IL-2, and IL-13 secretion, IL-10Rα blockade preferentially restores IFN-γ production. In viremic subjects, combined PD-L1/IL-10Rα blockade results in a striking 10-fold increase in IFN-γ secretion by HIV-1-specific CD4 T cells that is not observed in subjects with spontaneous (elite controllers) or therapy-induced control of viral replication. In contrast to the dramatic increase in IFN-γ production, concurrent blockade has a marginal additive effect on IL-2 production, IL-13 secretion, and HIV-1-specific CD4 T cell proliferation. IFN-γ produced by Thelper cells upregulates PD-L1, HLA I/II, and IL-12 expression by monocytes. The effect of combined blockade on IFN-γ was dependent on reciprocal reinforcement through IL-12. These studies provide crucial information on the different immunoregulatory qualities of PD-1 and IL-10 in progressive disease and link exhausted virus-specific CD4 T cells and monocytes in the regulation of IFN-γ and IL-12 secretion.
IMPORTANCE:Infection with HIV results in most people in uncontrolled viral replication and progressive weakening of the body defenses. In the absence of antiviral therapy, this process results in clinical disease, or AIDS. An important reason why HIV continues to multiply is that a population of white blood cells called CD4 T cells that targets the virus fails to work properly. At least part of this impairment is under the control of inhibitory mechanisms that can be blocked to improve the function of these CD4 T cells. In this report, we show that blocking one or two of the molecules involved, called PD-1 and IL-10, has different effects on the individual functions of these cells and that one is strongly improved. We investigate how these effects are caused by interactions between CD4 T cells and antigen-presenting cells. These observations can have implications for new therapeutic approaches in HIV infection.
Differential impact of PD-1 and/or interleukin-10 blockade on HIV-1-specific CD4 T cell and antigen-presenting cell functions.
Porichis F, Hart MG, Zupkosky J, Barblu L, Kwon DS, McMullen A, Brennan T, Ahmed R, Freeman GJ, Kavanagh DG, Kaufmann DE.
Journal of virology. 2014; 88(5):2508-18.
Electron tomography of HIV-1 infection in gut-associated lymphoid tissue - PLoS Pathogens - 2014
Critical aspects of HIV-1 infection occur in mucosal tissues, particularly in the gut, which contains large numbers of HIV-1 target cells that are depleted early in infection. We used electron tomography (ET) to image HIV-1 in gut-associated lymphoid tissue (GALT) of HIV-1-infected humanized mice, the first three-dimensional ultrastructural examination of HIV-1 infection in vivo. Human immune cells were successfully engrafted in the mice, and following infection with HIV-1, human T cells were reduced in GALT. Virions were found by ET at all stages of egress, including budding immature virions and free mature and immature viruses. Immuno-electron microscopy verified the virions were HIV-1 and showed CD4 sequestration in the endoplasmic reticulum of infected cells. Observation of HIV-1 in infected GALT tissue revealed that most HIV-1-infected cells, identified by immunolabeling and/or the presence of budding virions, were localized to intestinal crypts with pools of free virions concentrated in spaces between cells. Fewer infected cells were found in mucosal regions and the lamina propria. The preservation quality of reconstructed tissue volumes allowed details of budding virions, including structures interpreted as host-encoded scission machinery, to be resolved. Although HIV-1 virions released from infected cultured cells have been described as exclusively mature, we found pools of both immature and mature free virions within infected tissue. The pools could be classified as containing either mostly mature or mostly immature particles, and analyses of their proximities to the cell of origin supported a model of semi-synchronous waves of virion release. In addition to HIV-1 transmission by pools of free virus, we found evidence of transmission via virological synapses. Three-dimensional EM imaging of an active infection within tissue revealed important differences between cultured cell and tissue infection models and furthered the ultrastructural understanding of HIV-1 transmission within lymphoid tissue.
Electron tomography of HIV-1 infection in gut-associated lymphoid tissue.
Ladinsky MS, Kieffer C, Olson G, Deruaz M, Vrbanac V, Tager AM, Kwon DS, Bjorkman PJ.
PLoS pathogens. 2014; 10(1):e1003899.
Regulatory T cells expanded from HIV-1-infected individuals maintain phenotype, TCR repertoire and suppressive capacity - PLoS One - 2014
While modulation of regulatory T cell (Treg) function and adoptive Treg transfer are being explored as therapeutic modalities in the context of autoimmune diseases, transplantation and cancer, their role in HIV-1 pathogenesis remains less well defined. Controversy persists regarding their beneficial or detrimental effects in HIV-1 disease, which warrants further detailed exploration. Our objectives were to investigate if functional CD4(+) Tregs can be isolated and expanded from HIV-1-infected individuals for experimental or potential future therapeutic use and to determine phenotype and suppressive capacity of expanded Tregs from HIV-1 positive blood and tissue. Tregs and conventional T cell controls were isolated from blood and gut-associated lymphoid tissue of individuals with HIV-1 infection and healthy donors using flow-based cell-sorting. The phenotype of expanded Tregs was assessed by flow-cytometry and quantitative PCR. T-cell receptor ß-chain (TCR-β) repertoire diversity was investigated by deep sequencing. Flow-based T-cell proliferation and chromium release cytotoxicity assays were used to determine Treg suppressive function. Tregs from HIV-1 positive individuals, including infants, were successfully expanded from PBMC and GALT. Expanded Tregs expressed high levels of FOXP3, CTLA4, CD39 and HELIOS and exhibited a highly demethylated TSDR (Treg-specific demethylated region), characteristic of Treg lineage. The TCRß repertoire was maintained following Treg expansion and expanded Tregs remained highly suppressive in vitro. Our data demonstrate that Tregs can be expanded from blood and tissue compartments of HIV-1+ donors with preservation of Treg phenotype, function and TCR repertoire. These results are highly relevant for the investigation of potential future therapeutic use, as currently investigated for other disease states and hold great promise for detailed studies on the role of Tregs in HIV-1 infection.
Regulatory T cells expanded from HIV-1-infected individuals maintain phenotype, TCR repertoire and suppressive capacity.
Angin M, Klarenbeek PL, King M, Sharma SM, Moodley ES, Rezai A, Piechocka-Trocha A, Toth I, Chan AT, Goulder PJ, Ndung’u T, Kwon DS, Addo MM.
PloS one. 2014; 9(2):e86920.
Temporal effect of HLA-B*57 on viral control during primary HIV-1 infection - Retrovirology - 2013
HLA-B alleles are associated with viral control in chronic HIV-1 infection, however, their role in primary HIV-1 disease is unclear. This study sought to determine the role of HLA-B alleles in viral control during the acute phase of HIV-1 infection and establishment of the early viral load set point (VLSP).
Individuals identified during primary HIV-1 infection were HLA class I typed and followed longitudinally. Associations between HLA-B alleles and HIV-1 viral replication during acute infection and VLSP were analyzed in untreated subjects. The results showed that neither HLA-B*57 nor HLA-B*27 were significantly associated with viral control during acute HIV-1 infection (Fiebig stage I-IV, n=171). HLA-B*57 was however significantly associated with a subsequent lower VLSP (p<0.001, n=135) with nearly 1 log10 less median viral load. Analysis of a known polymorphism at position 97 of HLA-B showed significant associations with both lower initial viral load (p<0.01) and lower VLSP (p<0.05). However, this association was dependent on different amino acids at this position for each endpoint.
The effect of HLA-B*57 on viral control is more pronounced during the later stages of primary HIV-1 infection, which suggests the underlying mechanism of control occurs at a critical period in the first several months after HIV-1 acquisition. The risk profile of polymorphisms at position 97 of HLA-B are more broadly associated with HIV-1 viral load during primary infection and may serve as a focal point in further studies of HLA-B function.
Temporal effect of HLA-B*57 on viral control during primary HIV-1 infection.
Vaidya SA, Streeck H, Beckwith N, Ghebremichael M, Pereyra F, Kwon DS, Addo MM, Rychert J, Routy JP, Jessen H, Kelleher AD, Hecht F, Sekaly RP, Carrington M, Walker BD, Allen TM, Rosenberg ES, Altfeld M.
Retrovirology. 2013; 10:139.
Single cells from human primary colorectal tumors exhibit polyfunctional heterogeneity in secretions of ELR+ CXC chemokines - Integrative Biology - 2013
Cancer is an inflammatory disease of tissue that is largely influenced by the interactions between multiple cell types, secreted factors, and signal transduction pathways. While single-cell sequencing continues to refine our understanding of the clonotypic heterogeneity within tumors, the complex interplay between genetic variations and non-genetic factors ultimately affects therapeutic outcome. Much has been learned through bulk studies of secreted factors in the tumor microenvironment, but the secretory behavior of single cells has been largely uncharacterized. Here we directly profiled the secretions of ELR+ CXC chemokines from thousands of single colorectal tumor and stromal cells, using an array of subnanoliter wells and a technique called microengraving to characterize both the rates of secretion of several factors at once and the numbers of cells secreting each chemokine. The ELR+ CXC chemokines are highly redundant, pro-angiogenic cytokines that signal via the CXCR1 and CXCR2 receptors, influencing tumor growth and progression. We find that human primary colorectal tumor and stromal cells exhibit polyfunctional heterogeneity in the combinations and magnitudes of secretions for these chemokines. In cell lines, we observe similar variance: phenotypes observed in bulk can be largely absent among the majority of single cells, and discordances exist between secretory states measured and gene expression for these chemokines among single cells. Together, these measures suggest secretory states among tumor cells are complex and can evolve dynamically. Most importantly, this study reveals new insight into the intratumoral phenotypic heterogeneity of human primary tumors.
Single cells from human primary colorectal tumors exhibit polyfunctional heterogeneity in secretions of ELR+ CXC chemokines.
Adalsteinsson VA, Tahirova N, Tallapragada N, Yao X, Campion L, Angelini A, Douce TB, Huang C, Bowman B, Williamson CA, Kwon DS, Wittrup KD, Love JC.
Integrative biology : quantitative biosciences from nano to macro. 2013; 5(10):1272-81. NIHMSID: NIHMS583590
Fine-mapping classical HLA variation associated with durable host control of HIV-1 infection in African Americans - Human Molecular Genetics - 2012
A small proportion of human immunodeficiency virus-1 (HIV-1) infected individuals, termed HIV-1 controllers, suppress viral replication to very low levels in the absence of therapy. Genetic investigations of this phenotype have strongly implicated variation in the class I major histocompatibility complex (MHC) region as key to HIV-1 control. We collected sequence-based classical class I HLA genotypes at 4-digit resolution in HIV-1-infected African American controllers and progressors (n = 1107), and tested them for association with host control using genome-wide single nucleotide polymorphism data to account for population structure. Several classical alleles at HLA-B were associated with host control, including B*57:03 [odds ratio (OR) = 5.1; P= 3.4 × 10(-18)] and B*81:01 (OR = 4.8; P= 1.3 × 10(-9)). Analysis of variable amino acid positions demonstrates that HLA-B position 97 is the most significant association with host control in African Americans (omnibus P = 1.2 × 10(-21)) and explains the signal of several HLA-B alleles, including B*57:03. Within HLA-B, we also identified independent effects at position 116 (omnibus P= 2.8 × 10(-15)) in the canonical F pocket, position 63 in the B pocket (P= 1.5 × 10(-3)) and the non-pocket position 245 (P= 8.8 × 10(-10)), which is thought to influence CD8-binding kinetics. Adjusting for these HLA-B effects, there is evidence for residual association in the MHC region. These results underscore the key role of HLA-B in affecting HIV-1 replication, likely through the molecular interaction between HLA-B and viral peptides presented by infected cells, and suggest that sites outside the peptide-binding pocket also influence HIV-1 control.
Fine-mapping classical HLA variation associated with durable host control of HIV-1 infection in African Americans.
McLaren PJ, Ripke S, Pelak K, Weintrob AC, Patsopoulos NA, Jia X, Erlich RL, Lennon NJ, Kadie CM, Heckerman D, Gupta N, Haas DW, Deeks SG, Pereyra F, Walker BD, de Bakker PI.
Human molecular genetics. 2012; 21(19):4334-47.
CD4+ CD25+ regulatory T cells impair HIV-1-specific CD4 T cell responses by upregulating interleukin-10 production in monocytes - Journal of Virology - 2012
T cell dysfunction in the presence of ongoing antigen exposure is a cardinal feature of chronic viral infections with persistent high viremia, including HIV-1. Although interleukin-10 (IL-10) has been implicated as an important mediator of this T cell dysfunction, the regulation of IL-10 production in chronic HIV-1 infection remains poorly understood. We demonstrated that IL-10 is elevated in the plasma of individuals with chronic HIV-1 infection and that blockade of IL-10 signaling results in a restoration of HIV-1-specific CD4 T cell proliferation, gamma interferon (IFN-γ) secretion, and, to a lesser extent, IL-2 production. Whereas IL-10 blockade leads to restoration of IFN-γ secretion by HIV-1-specific CD4 T cells in all categories of subjects investigated, significant enhancement of IL-2 production and improved proliferation of CD4 T helper cells are restricted to viremic individuals. In peripheral blood mononuclear cells (PBMCs), this IL-10 is produced primarily by CD14(+) monocytes, but its production is tightly controlled by regulatory T cells (Tregs), which produce little IL-10 directly. When Tregs are depleted from PBMCs of viremic individuals, the effect of the IL-10 signaling blockade is abolished and IL-10 production by monocytes decreases, while the production of proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-α), increases. The regulation of IL-10 by Tregs appears to be mediated primarily by contact or paracrine-dependent mechanisms which involve IL-27. This work describes a novel mechanism by which regulatory T cells control IL-10 production and contribute to dysfunctional HIV-1-specific CD4 T cell help in chronic HIV-1 infection and provides a unique mechanistic insight into the role of regulatory T cells in immune exhaustion.
CD4+ CD25+ regulatory T cells impair HIV-1-specific CD4 T cell responses by upregulating interleukin-10 production in monocytes.
Kwon DS, Angin M, Hongo T, Law KM, Johnson J, Porichis F, Hart MG, Pavlik DF, Tighe DP, Kavanagh DG, Streeck H, Addo MM, Kaufmann DE.
Journal of virology. 2012; 86(12):6586-94.
Preserved function of regulatory T cells in chronic HIV-1 infection despite decreased numbers in blood and tissue - The Journal of Infectious Diseases - 2012
Regulatory T cells (Tregs) are potent immune modulators, but their role in human immunodeficiency virus type 1 (HIV-1) pathogenesis remains poorly understood. We performed a detailed analysis of the frequency and function of Tregs in a large cohort of HIV-1-infected individuals and HIV-1 negative controls. While HIV “elite controllers” and uninfected individuals had similar Treg numbers and frequencies, the absolute numbers of Tregs declined in blood and gut-associated lymphoid tissue in patients with chronic progressive HIV-1 infection. Despite quantitative changes in Tregs, HIV-1 infection was not associated with an impairment of ex vivo suppressive function of flow-sorted Tregs in both HIV controllers and untreated chronic progressors.
Preserved function of regulatory T cells in chronic HIV-1 infection despite decreased numbers in blood and tissue.
Angin M, Kwon DS, Streeck H, Wen F, King M, Rezai A, Law K, Hongo TC, Pyo A, Piechocka-Trocha A, Toth I, Pereyra F, Ghebremichael M, Rodig SJ, Milner DA Jr, Richter JM, Altfeld M, Kaufmann DE, Walker BD, Addo MM.
The Journal of infectious diseases. 2012; 205(10):1495-500.
Rapid, efficient functional characterization and recovery of HIV-specific human CD8+ T cells using microengraving - Proceedings of the National Academy of Sciences - 2012
The nature of certain clinical samples (tissue biopsies, fluids) or the subjects themselves (pediatric subjects, neonates) often constrain the number of cells available to evaluate the breadth of functional T-cell responses to infections or therapeutic interventions. The methods most commonly used to assess this functional diversity ex vivo and to recover specific cells to expand in vitro usually require more than 10(6) cells. Here we present a process to identify antigen-specific responses efficiently ex vivo from 10(4)-10(5) single cells from blood or mucosal tissues using dense arrays of subnanoliter wells. The approach combines on-chip imaging cytometry with a technique for capturing secreted proteins–called “microengraving”–to enumerate antigen-specific responses by single T cells in a manner comparable to conventional assays such as ELISpot and intracellular cytokine staining. Unlike those assays, however, the individual cells identified can be recovered readily by micromanipulation for further characterization in vitro. Applying this method to assess HIV-specific T-cell responses demonstrates that it is possible to establish clonal CD8(+) T-cell lines that represent the most abundant specificities present in circulation using 100- to 1,000-fold fewer cells than traditional approaches require and without extensive genotypic analysis a priori. This rapid (<24 h), efficient, and inexpensive process should improve the comparative study of human T-cell immunology across ages and anatomic compartments.
Rapid, efficient functional characterization and recovery of HIV-specific human CD8+ T cells using microengraving.
Varadarajan N, Kwon DS, Law KM, Ogunniyi AO, Anahtar MN, Richter JM, Walker BD, Love JC.
Proceedings of the National Academy of Sciences of the United States of America. 2012; 109(10):3885-90.
Altered distribution of mucosal NK cells during HIV infection - Mucosal Immunology - 2012
The human gut mucosa is a major site of human immunodeficiency virus (HIV) infection and infection-associated pathogenesis. Increasing evidence shows that natural killer (NK) cells have an important role in control of HIV infection, but the mechanism(s) by which they mediate antiviral activity in the gut is unclear. Here, we show that two distinct subsets of NK cells exist in the gut, one localized to intraepithelial spaces (intraepithelial lymphocytes, IELs) and the other to the lamina propria (LP). The frequency of both subsets of NK cells was reduced in chronic infection, whereas IEL NK cells remained stable in spontaneous controllers with protective killer immunoglobulin-like receptor/human leukocyte antigen genotypes. Both IEL and LP NK cells were significantly expanded in immunological non-responsive patients, who incompletely recovered CD4+ T cells on highly active antiretroviral therapy (HAART). These data suggest that both IEL and LP NK cells may expand in the gut in an effort to compensate for compromised CD4+ T-cell recovery, but that only IEL NK cells may be involved in providing durable control of HIV in the gut.
Altered distribution of mucosal NK cells during HIV infection.
Sips M, Sciaranghella G, Diefenbach T, Dugast AS, Berger CT, Liu Q, Kwon D, Ghebremichael M, Estes JD, Carrington M, Martin JN, Deeks SG, Hunt PW, Alter G.
Mucosal immunology. 2012; 5(1):30-40. NIHMSID: NIHMS327486
Responsiveness of HIV-specific CD4 T cells to PD-1 blockade - Blood - 2011
Defining the T helper functions impaired by programmed death-1 (PD-1) is crucial for understanding its role in defective HIV control and determining the therapeutic potential of targeting this inhibitory pathway. We describe here the relationships among disease stage, levels of PD-1 expression, and reversibility of CD4 T-cell impairment. PD-L1 blockade in vitro enhanced HIV-specific production of Th0 (IL-2), Th1 (IFN-γ), Th2 (IL-13), and TFH (IL-21) cytokines by CD4 T cells. PD-L1 blockade caused an early increase in cytokine transcription and translation that preceded cell proliferation. Although the impact of PD-L1 blockade on cytokine expression and, to a lesser extent, cell proliferation was associated with markers of disease progression, restoration of cytokine secretion was also observed in most subjects with undetectable viremia. PD-L1 blockade restored cytokine secretion in both PD-1intermediate and PD-1high sorted CD4 T-cell subsets. Compared with PD-1high HIV-specific CD8 T cells, PD-1high HIV-specific CD4 T cells showed lower expression of the inhibitory molecules CD160 and 2B4, demonstrating marked differences in expression of inhibitory receptors between T-cell subsets. These data show that PD-1 impairs HIV-specific T helper responses both by limiting expansion of these cells and by inhibiting effector functions of multiple differentiated CD4 T-cell subsets.
Responsiveness of HIV-specific CD4 T cells to PD-1 blockade.
Porichis F, Kwon DS, Zupkosky J, Tighe DP, McMullen A, Brockman MA, Pavlik DF, Rodriguez-Garcia M, Pereyra F, Freeman GJ, Kavanagh DG, Kaufmann DE.
Blood. 2011; 118(4):965-74.
Epithelial adhesion molecules can inhibit HIV-1-specific CD8⁺ T-cell functions - Blood - 2011
Under persistent antigenic stimulation, virus-specific CD8⁺ T cells become increasingly dysfunctional and up-regulate several inhibitory molecules such as killer lectin-like receptor G1 (KLRG1). Here, we demonstrate that HIV-1 antigen-specific T cells from subjects with chronic-progressive HIV-1 infection have significantly elevated KLRG1 expression (P < .001); show abnormal distribution of E-cadherin, the natural ligand of KLRG1, in the intestinal mucosa; and have elevated levels of systemic soluble E-cadherin (sE-cadherin) that significantly correlate with HIV-1 viral load (R = 0.7, P = .004). We furthermore demonstrate that in the presence of sE-cadherin, KLRG1(hi) HIV-1-specific CD8⁺ T cells are impaired in their ability to respond by cytokine secretion on antigenic stimulation (P = .002) and to inhibit viral replication (P = .03) in vitro. Thus, these data suggest a critical mechanism by which the disruption of the intestinal epithelium associated with HIV-1 leads to increased systemic levels of sE-cadherin, which inhibits the effector functions of KLRG1(hi)-expressing HIV-1-specific CD8⁺ T cells systemically.
Epithelial adhesion molecules can inhibit HIV-1-specific CD8⁺ T-cell functions.
Streeck H, Kwon DS, Pyo A, Flanders M, Chevalier MF, Law K, Jülg B, Trocha K, Jolin JS, Anahtar MN, Lian J, Toth I, Brumme Z, Chang JJ, Caron T, Rodig SJ, Milner DA Jr, Piechoka-Trocha A, Kaufmann DE, Walker BD, Altfeld M.
Blood. 2011; 117(19):5112-22.
HIV-1-specific interleukin-21+ CD4+ T cell responses contribute to durable viral control through the modulation of HIV-specific CD8+ T cell function. - Journal of Virology - 2011
Functional defects in cytotoxic CD8(+) T cell responses arise in chronic human viral infections, but the mechanisms involved are not well understood. In mice, CD4 cell-mediated interleukin-21 (IL-21) production is necessary for the maintenance of CD8(+) T cell function and control of persistent viral infections. To investigate the potential role of IL-21 in a chronic human viral infection, we studied the rare subset of HIV-1 controllers, who are able to spontaneously control HIV-1 replication without treatment. HIV-specific triggering of IL-21 by CD4(+) T cells was significantly enriched in these persons (P = 0.0007), while isolated loss of IL-21-secreting CD4(+) T cells was characteristic for subjects with persistent viremia and progressive disease. IL-21 responses were mediated by recognition of discrete epitopes largely in the Gag protein, and expansion of IL-21(+) CD4(+) T cells in acute infection resulted in lower viral set points (P = 0.002). Moreover, IL-21 production by CD4(+) T cells of HIV controllers enhanced perforin production by HIV-1-specific CD8(+) T cells from chronic progressors even in late stages of disease, and HIV-1-specific effector CD8(+) T cells showed an enhanced ability to efficiently inhibit viral replication in vitro after IL-21 binding. These data suggest that HIV-1-specific IL-21(+) CD4(+) T cell responses might contribute to the control of viral replication in humans and are likely to be of great importance for vaccine design.
HIV-1-specific interleukin-21+ CD4+ T cell responses contribute to durable viral control through the modulation of HIV-specific CD8+ T cell function.
Chevalier MF, Jülg B, Pyo A, Flanders M, Ranasinghe S, Soghoian DZ, Kwon DS, Rychert J, Lian J, Muller MI, Cutler S, McAndrew E, Jessen H, Pereyra F, Rosenberg ES, Altfeld M, Walker BD, Streeck H.
Journal of virology. 2011; 85(2):733-41.
The major genetic determinants of HIV-1 control affect HLA class I peptide presentation - Science - 2010
Infectious and inflammatory diseases have repeatedly shown strong genetic associations within the major histocompatibility complex (MHC); however, the basis for these associations remains elusive. To define host genetic effects on the outcome of a chronic viral infection, we performed genome-wide association analysis in a multiethnic cohort of HIV-1 controllers and progressors, and we analyzed the effects of individual amino acids within the classical human leukocyte antigen (HLA) proteins. We identified >300 genome-wide significant single-nucleotide polymorphisms (SNPs) within the MHC and none elsewhere. Specific amino acids in the HLA-B peptide binding groove, as well as an independent HLA-C effect, explain the SNP associations and reconcile both protective and risk HLA alleles. These results implicate the nature of the HLA-viral peptide interaction as the major factor modulating durable control of HIV infection.
The major genetic determinants of HIV-1 control affect HLA class I peptide presentation.
Pereyra F, Jia X, McLaren PJ, Telenti A, de Bakker PI, Walker BD, Ripke S, Brumme CJ, Pulit SL, Carrington M, Kadie CM, Carlson JM, Heckerman D, Graham RR, Plenge RM, Deeks SG, Gianniny L, Crawford G, Sullivan J, Gonzalez E, Davies L, Camargo A, Moore JM, Beattie N, Gupta S, Crenshaw A, Burtt NP, Guiducci C, Gupta N, Gao X, Qi Y, Yuki Y, Piechocka-Trocha A, Cutrell E, Rosenberg R, Moss KL, Lemay P, O’Leary J, Schaefer T, Verma P, Toth I, Block B, Baker B, Rothchild A, Lian J, Proudfoot J, Alvino DM, Vine S, Addo MM, Allen TM, Altfeld M, Henn MR, Le Gall S, Streeck H, Haas DW, Kuritzkes DR, Robbins GK, Shafer RW, Gulick RM, Shikuma CM, Haubrich R, Riddler S, Sax PE, Daar ES, Ribaudo HJ, Agan B, Agarwal S, Ahern RL, Allen BL, Altidor S, Altschuler EL, Ambardar S, Anastos K, Anderson B, Anderson V, Andrady U, Antoniskis D, Bangsberg D, Barbaro D, Barrie W, Bartczak J, Barton S, Basden P, Basgoz N, Bazner S, Bellos NC, Benson AM, Berger J, Bernard NF, Bernard AM, Birch C, Bodner SJ, Bolan RK, Boudreaux ET, Bradley M, Braun JF, Brndjar JE, Brown SJ, Brown K, Brown ST, Burack J, Bush LM, Cafaro V, Campbell O, Campbell J, Carlson RH, Carmichael JK, Casey KK, Cavacuiti C, Celestin G, Chambers ST, Chez N, Chirch LM, Cimoch PJ, Cohen D, Cohn LE, Conway B, Cooper DA, Cornelson B, Cox DT, Cristofano MV, Cuchural G Jr, Czartoski JL, Dahman JM, Daly JS, Davis BT, Davis K, Davod SM, DeJesus E, Dietz CA, Dunham E, Dunn ME, Ellerin TB, Eron JJ, Fangman JJ, Farel CE, Ferlazzo H, Fidler S, Fleenor-Ford A, Frankel R, Freedberg KA, French NK, Fuchs JD, Fuller JD, Gaberman J, Gallant JE, Gandhi RT, Garcia E, Garmon D, Gathe JC Jr, Gaultier CR, Gebre W, Gilman FD, Gilson I, Goepfert PA, Gottlieb MS, Goulston C, Groger RK, Gurley TD, Haber S, Hardwicke R, Hardy WD, Harrigan PR, Hawkins TN, Heath S, Hecht FM, Henry WK, Hladek M, Hoffman RP, Horton JM, Hsu RK, Huhn GD, Hunt P, Hupert MJ, Illeman ML, Jaeger H, Jellinger RM, John M, Johnson JA, Johnson KL, Johnson H, Johnson K, Joly J, Jordan WC, Kauffman CA, Khanlou H, Killian RK, Kim AY, Kim DD, Kinder CA, Kirchner JT, Kogelman L, Kojic EM, Korthuis PT, Kurisu W, Kwon DS, LaMar M, Lampiris H, Lanzafame M, Lederman MM, Lee DM, Lee JM, Lee MJ, Lee ET, Lemoine J, Levy JA, Llibre JM, Liguori MA, Little SJ, Liu AY, Lopez AJ, Loutfy MR, Loy D, Mohammed DY, Man A, Mansour MK, Marconi VC, Markowitz M, Marques R, Martin JN, Martin HL Jr, Mayer KH, McElrath MJ, McGhee TA, McGovern BH, McGowan K, McIntyre D, Mcleod GX, Menezes P, Mesa G, Metroka CE, Meyer-Olson D, Miller AO, Montgomery K, Mounzer KC, Nagami EH, Nagin I, Nahass RG, Nelson MO, Nielsen C, Norene DL, O’Connor DH, Ojikutu BO, Okulicz J, Oladehin OO, Oldfield EC 3rd, Olender SA, Ostrowski M, Owen WF Jr, Pae E, Parsonnet J, Pavlatos AM, Perlmutter AM, Pierce MN, Pincus JM, Pisani L, Price LJ, Proia L, Prokesch RC, Pujet HC, Ramgopal M, Rathod A, Rausch M, Ravishankar J, Rhame FS, Richards CS, Richman DD, Rodes B, Rodriguez M, Rose RC 3rd, Rosenberg ES, Rosenthal D, Ross PE, Rubin DS, Rumbaugh E, Saenz L, Salvaggio MR, Sanchez WC, Sanjana VM, Santiago S, Schmidt W, Schuitemaker H, Sestak PM, Shalit P, Shay W, Shirvani VN, Silebi VI, Sizemore JM Jr, Skolnik PR, Sokol-Anderson M, Sosman JM, Stabile P, Stapleton JT, Starrett S, Stein F, Stellbrink HJ, Sterman FL, Stone VE, Stone DR, Tambussi G, Taplitz RA, Tedaldi EM, Telenti A, Theisen W, Torres R, Tosiello L, Tremblay C, Tribble MA, Trinh PD, Tsao A, Ueda P, Vaccaro A, Valadas E, Vanig TJ, Vecino I, Vega VM, Veikley W, Wade BH, Walworth C, Wanidworanun C, Ward DJ, Warner DA, Weber RD, Webster D, Weis S, Wheeler DA, White DJ, Wilkins E, Winston A, Wlodaver CG, van’t Wout A, Wright DP, Yang OO, Yurdin DL, Zabukovic BW, Zachary KC, Zeeman B, Zhao M.
Science (New York, N.Y.). 2010; 330(6010):1551-7. NIHMSID: NIHMS331514
Transcriptional analysis of HIV-specific CD8+ T cells shows that PD-1 inhibits T cell function by upregulating BATF - Nature Medicine - 2010
CD8(+) T cells in chronic viral infections such as HIV develop functional defects including loss of interleukin-2 (IL-2) secretion and decreased proliferative potential that are collectively termed ‘exhaustion’. Exhausted T cells express increased amounts of multiple inhibitory receptors, such as programmed death-1 (PD-1), that contribute to impaired virus-specific T cell function. Although reversing PD-1 inhibition is therefore an attractive therapeutic strategy, the cellular mechanisms by which PD-1 ligation results in T cell inhibition are not fully understood. PD-1 is thought to limit T cell activation by attenuating T cell receptor (TCR) signaling. It is not known whether PD-1 also acts by upregulating genes in exhausted T cells that impair their function. Here we analyzed gene expression profiles from HIV-specific CD8(+) T cells in individuals with HIV and show that PD-1 coordinately upregulates a program of genes in exhausted CD8(+) T cells from humans and mice. This program includes upregulation of basic leucine transcription factor, ATF-like (BATF), a transcription factor in the AP-1 family. Enforced expression of BATF was sufficient to impair T cell proliferation and cytokine secretion, whereas BATF knockdown reduced PD-1 inhibition. Silencing BATF in T cells from individuals with chronic viremia rescued HIV-specific T cell function. Thus, inhibitory receptors can cause T cell exhaustion by upregulating genes–such as BATF–that inhibit T cell function. Such genes may provide new therapeutic opportunities to improve T cell immunity to HIV.
Transcriptional analysis of HIV-specific CD8+ T cells shows that PD-1 inhibits T cell function by upregulating BATF.
Quigley M, Pereyra F, Nilsson B, Porichis F, Fonseca C, Eichbaum Q, Julg B, Jesneck JL, Brosnahan K, Imam S, Russell K, Toth I, Piechocka-Trocha A, Dolfi D, Angelosanto J, Crawford A, Shin H, Kwon DS, Zupkosky J, Francisco L, Freeman GJ, Wherry EJ, Kaufmann DE, Walker BD, Ebert B, Haining WN.
Nature medicine. 2010; 16(10):1147-51. NIHMSID: NIHMS234681
Protective and detrimental roles of IL-10 in HIV pathogenesis - European Cytokine Network - 2010
Successful pathogen clearance depends on a finely orchestrated equilibrium between inflammatory immune responses and immunoregulatory mechanisms that limit collateral tissue damage. The cytokine interleukin 10 (IL-10) has been shown to play a critical role in this balance in numerous infectious diseases. Studies in animal models have revealed that IL-10 gene-knockout or signaling blockade can enhance resistance to pathogens, and substantially facilitate viral clearance. These same interventions in other infections however, result in more severe disease due to the inability of the immune system to adequately contain the pathogen load, and to control immune-mediate damage. This IL-10-regulated balance is also apparent in human infectious diseases. This review summarizes evidence that IL-10 impacts many aspects of HIV pathogenesis, including the regulation of HIV-specific CD4 and CD8 T cell functions, as well as modulation of HIV-replication in PBMC subsets. Genetic polymorphisms in the IL-10 gene promoter that lead to decreased IL-10 expression have been associated with more rapid disease progression in late stages of HIV infection, suggesting that the anti-inflammatory effects of IL-10 may be protective in the setting of chronic immune activation. We conclude with a discussion of important questions remaining, and the potential for therapeutic intervention based on manipulation of the IL-10 pathway.
Protective and detrimental roles of IL-10 in HIV pathogenesis.
Kwon DS, Kaufmann DE. European cytokine network. 2010; 21(3):208-14.
Human immunodeficiency virus type 1-specific CD8+ T-cell responses during primary infection are major determinants of the viral set point and loss of CD4+ T cells - Journal of Virology - 2009
Primary HIV-1 infection (PHI) is marked by a flu-like syndrome and high levels of viremia that decrease to a viral set point with the first emergence of virus-specific CD8+ T-cell responses. Here, we investigated in a large cohort of 527 subjects the immunodominance pattern of the first virus-specific cytotoxic T-lymphocyte (CTL) responses developed during PHI in comparison to CTL responses in chronic infection and demonstrated a distinct relationship between the early virus-specific CTL responses and the viral set point, as well as the slope of CD4+ T-cell decline. CTL responses during PHI followed clear hierarchical immunodominance patterns that were lost during the transition to chronic infection. Importantly, the immunodominance patterns of human immunodeficiency virus type 1 (HIV-1)-specific CTL responses detected in primary, but not in chronic, HIV-1 infection were significantly associated with the subsequent set point of viral replication. Moreover, the preservation of the initial CD8+ T-cell immunodominance patterns from the acute into the chronic phase of infection was significantly associated with slower CD4+ T-cell decline. Taken together, these data show that the specificity of the initial CTL response to HIV is critical for the subsequent control of viremia and have important implications for the rational selection of antigens for future HIV-1 vaccines.
Human immunodeficiency virus type 1-specific CD8+ T-cell responses during primary infection are major determinants of the viral set point and loss of CD4+ T cells.
Streeck H, Jolin JS, Qi Y, Yassine-Diab B, Johnson RC, Kwon DS, Addo MM, Brumme C, Routy JP, Little S, Jessen HK, Kelleher AD, Hecht FM, Sekaly RP, Rosenberg ES, Walker BD, Carrington M, Altfeld M. Journal of virology. 2009; 83(15):7641-8.
IL-10 is up-regulated in multiple cell types during viremic HIV infection and reversibly inhibits virus-specific T cells - Blood - 2009
Murine models indicate that interleukin-10 (IL-10) can suppress viral clearance, and interventional blockade of IL-10 activity has been proposed to enhance immunity in chronic viral infections. Increased IL-10 levels have been observed during HIV infection and IL-10 blockade has been shown to enhance T-cell function in some HIV-infected subjects. However, the categories of individuals in whom the IL-10 pathway is up-regulated are poorly defined, and the cellular sources of IL-10 in these subjects remain to be determined. Here we report that blockade of the IL-10 pathway augmented in vitro proliferative capacity of HIV-specific CD4 and CD8 T cells in individuals with ongoing viral replication. IL-10 blockade also increased cytokine secretion by HIV-specific CD4 T cells. Spontaneous IL-10 expression, measured as either plasma IL-10 protein or IL-10 mRNA in peripheral blood mononuclear cells (PBMCs), correlated positively with viral load and diminished after successful antiretroviral therapy. IL-10 mRNA levels were up-regulated in multiple PBMC subsets in HIV-infected subjects compared with HIV-negative controls, particularly in T, B, and natural killer (NK) cells, whereas monocytes were a major source of IL-10 mRNA in HIV-infected and -uninfected individuals. These data indicate that multiple cell types contribute to IL-10-mediated immune suppression in the presence of uncontrolled HIV viremia.
IL-10 is up-regulated in multiple cell types during viremic HIV infection and reversibly inhibits virus-specific T cells.
Brockman MA, Kwon DS, Tighe DP, Pavlik DF, Rosato PC, Sela J, Porichis F, Le Gall S, Waring MT, Moss K, Jessen H, Pereyra F, Kavanagh DG, Walker BD, Kaufmann DE. Blood. 2009; 114(2):346-56.
Posaconazole: a new broad-spectrum antifungal agent - Expert Opinion on Pharmacotherapy - 2007
The rising incidence of invasive fungal infections and the emergence of broader fungal resistance have led to the need for novel antifungal agents. Posaconazole is a new member of the triazole class of antifungals. It is available as an oral suspension and has a favorable toxicity profile, has demonstrated clinical efficacy in the treatment of oropharyngeal candidiasis and has shown promise as salvage therapy for invasive aspergillosis, zygomycosis, cryptococcal meningitis and a variety of other fungal infections. In addition, data from randomized controlled studies support its efficacy for use in prophylaxis of invasive fungal infections in patients who are severely immunocompromised. The wide spectrum activity of posaconazole in in vitro studies, animal models and preliminary clinical studies suggest that posaconazole represents an important addition to the antifungal armamentarium.
Posaconazole: a new broad-spectrum antifungal agent.
Kwon DS, Mylonakis E. Expert opinion on pharmacotherapy. 2007; 8(8):1167-78.
DC-SIGN-mediated internalization of HIV is required for trans-enhancement of T cell infection - Immunity - 2002
Fusion of the human immunodeficiency virus (HIV) to the plasma membrane of target cells is mediated by interaction of its envelope glycoprotein, gp120, with CD4 and appropriate chemokine receptors. gp120 additionally binds to DC-SIGN, a C-type lectin expressed on immature dendritic cells. This interaction does not result in viral fusion, but instead contributes to enhanced infection in trans of target cells that express CD4 and chemokine receptors. Here we show that DC-SIGN mediates rapid internalization of intact HIV into a low pH nonlysosomal compartment. Internalized virus retains competence to infect target cells. Removal of the DC-SIGN cytoplasmic tail reduced viral uptake and abrogated the trans-enhancement of T cell infection. We propose that HIV binds to DC-SIGN to gain access to an intracellular compartment that contributes to augmentation or retention of viral infectivity.
DC-SIGN-mediated internalization of HIV is required for trans-enhancement of T cell infection.
Kwon DS, Gregorio G, Bitton N, Hendrickson WA, Littman DR. Immunity. 2002; 16(1):135-44.
DC-SIGN, a dendritic cell-specific HIV-1-binding protein that enhances trans-infection of T cells - Cell - 2000
Dendritic cells (DC) capture microorganisms that enter peripheral mucosal tissues and then migrate to secondary lymphoid organs, where they present these in antigenic form to resting T cells and thus initiate adaptive immune responses. Here, we describe the properties of a DC-specific C-type lectin, DC-SIGN, that is highly expressed on DC present in mucosal tissues and binds to the HIV-1 envelope glycoprotein gp120. DC-SIGN does not function as a receptor for viral entry into DC but instead promotes efficient infection in trans of cells that express CD4 and chemokine receptors. We propose that DC-SIGN efficiently captures HIV-1 in the periphery and facilitates its transport to secondary lymphoid organs rich in T cells, to enhance infection in trans of these target cells.
DC-SIGN, a dendritic cell-specific HIV-1-binding protein that enhances trans-infection of T cells.
Geijtenbeek TB, Kwon DS, Torensma R, van Vliet SJ, van Duijnhoven GC, Middel J, Cornelissen IL, Nottet HS, KewalRamani VN, Littman DR, Figdor CG, van Kooyk Y. Cell. 2000; 100(5):587-97.
Natural infection of a homozygous delta24 CCR5 red-capped mangabey with an R2b-tropic simian immunodeficiency virus - The Journal of Experimental Medicine - 1998
A homozygous 24-bp deletion (Delta24) was found in the CC chemokine receptor 5 (CCR5) of 11 out of 15 red-capped mangabeys (RCMs), Cercocebus torquatus torquatus, both in Africa and in an American zoo. The CCR5 Delta24 defect encompassed eight amino acids in frame in the fourth transmembrane region. Unexpectedly, RCM-009, one of 11 homozygotes (Delta24CCR5/ Delta24CCR5), was found to be naturally infected with a divergent simian immunodeficiency virus (SIV) strain, which was not R5-tropic, but used CCR2b (R2b) as its major coreceptor. SIVrcmGab1 was the only R2b-tropic SIV among other divergent SIVs tested. Cells transfected with the Delta24 CCR5 did not support entry of R5-tropic SIVmac, SIVcpz, SIVmne, HIV-2, or HIV-1, and were also inactive in signal transduction mediated by beta-chemokines. At 86.6%, the Delta24 allelic frequency was significantly higher than that of the 32-bp deletion found in humans. The Delta24 frequency was 4.1% in 34 sooty mangabeys (SMs), a geographically isolated subspecies that was naturally infected with R5-tropic SIV. Finding identical deletions in two mangabey subspecies separated for 10,000 years or more dates the Delta24 CCR5 deletion as ancient. However, the source of the selective pressure for the high rate of CCR5 deletion in RCMs remains to be determined. The high allelic frequency of the Delta24 CCR5 in RCMs, in comparison to that of SMs, suggests that R2b-tropism may have been acquired by SIVrcm, as an adaptation to CCR5 genetic defects appeared in its host.
Natural infection of a homozygous delta24 CCR5 red-capped mangabey with an R2b-tropic simian immunodeficiency virus.
Chen Z, Kwon D, Jin Z, Monard S, Telfer P, Jones MS, Lu CY, Aguilar RF, Ho DD, Marx PA. The Journal of experimental medicine. 1998; 188(11):2057-65.
Use of coreceptors other than CCR5 by non-syncytium-inducing adult and pediatric isolates of human immunodeficiency virus type 1 is rare in vitro - Journal of Virology - 1998
We have tested a panel of pediatric and adult human immunodeficiency virus type 1 (HIV-1) primary isolates for the ability to employ the following proteins as coreceptors during viral entry: CCR1, CCR2b, CCR3, CCR4, CCR5, CCR8, CXCR4, Bonzo, BOB, GPR1, V28, US28, and APJ. Most non-syncytium-inducing isolates could utilize only CCR5. All syncytium-inducing viruses used CXCR4, some also employed V28, and one (DH123) used CCR8 and APJ as well. A longitudinal series of HIV-1 subtype B isolates from an infected infant and its mother utilized Bonzo efficiently, as well as CCR5. The maternal isolates, which were syncytium inducing, also used CXCR4, CCR8, V28, and APJ.
Use of coreceptors other than CCR5 by non-syncytium-inducing adult and pediatric isolates of human immunodeficiency virus type 1 is rare in vitro.
Zhang YJ, Dragic T, Cao Y, Kostrikis L, Kwon DS, Littman DR, KewalRamani VN, Moore JP. Journal of virology. 1998; 72(11):9337-44.
The amino terminus of human CCR5 is required for its function as a receptor for diverse human and simian immunodeficiency virus envelope glycoproteins - Virology - 1998
The chemokine receptor CCR5 plays a key role in the CD4-dependent entry of human and simian immunodeficiency viruses into target cells. We have mapped the interaction sites on CCR5 for a number of novel anti-CCR5 monoclonal antibodies and have used these to study the role of the CCR5 N-terminal ectodomain in viral entry and to demonstrate differential CCR5 epitope expression on different cell types. Deletions of the CCR5 amino terminal domain or substitution with equivalent regions from other chemokine receptors did not affect cell surface expression or reactivity with loop-specific antibodies, suggesting that the loop regions remained conformationally intact. Exchanges of the amino terminal segment of CCR5 with the equivalent domains of CCR1, CCR2, and CXCR4 did not significantly affect infection with virus pseudotyped with envelope glycoproteins (Envs) from HIV-2 and SIV, but substitution with the CXCR4 sequence abrogated entry mediated by Env from HIV-1. In contrast, deletion of the amino terminus abrogated CCR5 receptor activity for all viral Envs examined. These data indicate that the amino terminus of CCR5 has an essential role in entry mediated by diverse viral Envs but that the sequence requirements are more relaxed for the HIV-2 and SIV Envs compared to the HIV-1 Env examined. This suggests that different viral Envs make distinct and specific interactions with the amino terminus of CCR5. Viral Env utilization of CCR5 expressed on 293-T cells does not always correlate with the cellular tropism of the virus, and one possible explanation is that Env-accessible interaction sites on CCR5 differ on different cell types. We therefore analyzed binding of several anti-CCR5 monoclonal antibodies to cell lines and primary cells that express this chemokine receptor and found that whereas all antibodies bound to CCR5-transfected 293T cells, several did not bind to PBMC. The results suggest that CCR5 undergoes cell type specific structural modifications which may affect interaction with different HIV and SIV envelope glycoproteins.
The amino terminus of human CCR5 is required for its function as a receptor for diverse human and simian immunodeficiency virus envelope glycoproteins.
Hill CM, Kwon D, Jones M, Davis CB, Marmon S, Daugherty BL, DeMartino JA, Springer MS, Unutmaz D, Littman DR.
Virology. 1998; 248(2):357-71.
Tn10 and IS10 transposition and chromosome rearrangements: mechanism and regulation in vivo and in vitro - Current Topics in Microbiology and Immunology - 1996
Tn10 and IS10 transposition and chromosome rearrangements: mechanism and regulation in vivo and in vitro.
Kleckner N, Chalmers RM, Kwon D, Sakai J, Bolland S. Current topics in microbiology and immunology. 1996; 204:49-82.
Structural domains of IS10 transposase and reconstitution of transposition activity from proteolytic fragments lacking an interdomain linker - The Proceedings of the National Academy of Sciences - 1995
All of the DNA cleavage and strand transfer events required for transposition of insertion sequence IS10 are carried out by a 46-kDa IS10-encoded transposase protein. Limited proteolysis demonstrates that transposase has two principal structural domains, a 28-kDa N-terminal domain (N alpha beta; aa 1-246) and a 17-kDa C-terminal domain (C; aa 256-402). The two domains are connected by a 1-kDa proteolytic-sensitive linker region (aa 247-255). The N-terminal domain N alpha beta can be further subdivided into domains N alpha and N beta by a weaker protease-sensitive site located 6 kDa (53 aa) from the N terminus. The N beta and N alpha beta fragments are capable of nonspecific DNA binding as determined by Southwestern blot analysis. None of the fragments alone is capable of carrying out the first step of transposition, assembly of a synaptic complex containing a pair of transposon ends. Remarkably, complete transposition activity can be reconstituted by mixing fragment N alpha beta and fragment C, with or without the intervening linker region. We infer that the structural integrity of transposase during the transitions involved in the chemical steps of the transposition reaction is maintained independent of the linker, presumably by direct contacts between and among the principal domains. Reconstitution of activity in the absence of the linker region is puzzling, however, because mutations that block strand transfer or affect insertion specificity alter linker region residues. Additional reconstitution experiments demonstrate that the N alpha region is dispensable for formation of a synaptic complex but is required for complexes to undergo cleavage.
Structural domains of IS10 transposase and reconstitution of transposition activity from proteolytic fragments lacking an interdomain linker.
Kwon D, Chalmers RM, Kleckner N. Proceedings of the National Academy of Sciences of the United States of America. 1995; 92(18):8234-8.