AIDS/HIV
Abstract
Eradication of the HIV-1 latent reservoir represents the current paradigm to developing a cure for AIDS. HIV-1 has evolved multiple mechanisms to evade CD8 T cell responses, including HIV-1 Nef–mediated downregulation of MHC-I from the surface of infected cells. Nef transcripts and protein are detectable in samples from aviremic donors, suggesting that Nef expression in latently HIV-1–infected CD4 T cells protects them from immune-mediated clearance. Here, we tested 4 small molecule inhibitors of HIV-1 Nef in an in vitro primary CD4 T cell latency model and measured the ability of autologous ex vivo or HIV-1 peptide–expanded CD8 T cells to recognize and kill latently infected cells as a function of inhibitor treatment. Nef inhibition enhanced cytokine secretion by autologous CD8 T cells against latently HIV-1–infected targets in an IFN-γ release assay. Additionally, CD8 T cell–mediated elimination of latently HIV-1–infected cells was significantly enhanced following Nef blockade, measured as a reduction in the frequency of infected cells and Gag protein in cultures following viral outgrowth assays. We demonstrate for the first time to our knowledge that Nef blockade, in combination with HIV-specific CD8 T cell expansion, might be a feasible strategy to target the HIV-1 latent reservoir that should be tested further in vivo.
Authors
Shariq Mujib, Aamir Saiyed, Saleh Fadel, Ardalan Bozorgzad, Nasra Aidarus, Feng Yun Yue, Erika Benko, Colin Kovacs, Lori A. Emert-Sedlak, Thomas E. Smithgall, Mario A. Ostrowski
Abstract
Promising therapeutic approaches for eradicating HIV include transcriptional activation of provirus from latently infected cells using latency-reversing agents (LRAs) and immune-mediated clearance to purge reservoirs. Accurate detection of cells capable of producing viral antigens and virions, and the measurement of clearance of infected cells, is essential to assessing therapeutic efficacy. Here, we apply enhanced methodology extending the sensitivity limits for the rapid detection of subfemtomolar HIV gag p24 capsid protein in CD4+ T cells from ART-suppressed HIV+ individuals, and we show viral protein induction following treatment with LRAs. Importantly, we demonstrate that clinical administration of histone deacetylase inhibitors (HDACis; vorinostat and panobinostat) induced HIV gag p24, and ex vivo stimulation produced sufficient viral antigen to elicit immune-mediated cell killing using anti-gp120/CD3 bispecific antibody. These findings extend beyond classical nucleic acid endpoints, which are confounded by the predominance of mutated, defective proviruses and, of paramount importance, enable assessment of cells making HIV protein that can now be targeted by immunological approaches.
Authors
Guoxin Wu, Michael Swanson, Aarthi Talla, Donald Graham, Julie Strizki, Daniel Gorman, Richard J.O. Barnard, Wade Blair, Ole S. Søgaard, Martin Tolstrup, Lars Østergaard, Thomas A. Rasmussen, Rafick-Pierre Sekaly, Nancie M. Archin, David M. Margolis, Daria J. Hazuda, Bonnie J. Howell
Abstract
Gut-associated lymphoid tissues are enriched in CCR6+ Th17-polarized CD4+ T cells that contribute to HIV-1 persistence during antiretroviral therapy (ART). This raises the need for Th17-targeted immunotherapies. In an effort to identify mechanisms governing HIV-1 permissiveness/persistence in gut-homing Th17 cells, we analyzed the transcriptome of CCR6+ versus CCR6– T cells exposed to the gut-homing inducer retinoic acid (RA) and performed functional validations in colon biopsies of HIV-infected individuals receiving ART (HIV+ART). Although both CCR6+ and CCR6– T cells acquired gut-homing markers upon RA exposure, the modulation of unique sets of genes coincided with preferential HIV-1 replication in RA-treated CCR6+ T cells. This molecular signature included the upregulation of HIV-dependency factors acting at entry/postentry levels, such as the CCR5 and PI3K/Akt/mTORC1 signaling pathways. Of note, mTOR expression/phosphorylation was distinctively induced by RA in CCR6+ T cells. Consistently, mTOR inhibitors counteracted the effect of RA on HIV replication in vitro and viral reactivation in CD4+ T cells from HIV+ART individuals via postentry mechanisms independent of CCR5. Finally, CCR6+ versus CCR6– T cells infiltrating the colons of HIV+ART individuals expressed unique molecular signatures, including higher levels of CCR5, integrin β7, and mTOR phosphorylation. Together, our results identify mTOR as a druggable key regulator of HIV permissiveness in gut-homing CCR6+ T cells.
Authors
Delphine Planas, Yuwei Zhang, Patricia Monteiro, Jean-Philippe Goulet, Annie Gosselin, Nathalie Grandvaux, Thomas J. Hope, Ariberto Fassati, Jean-Pierre Routy, Petronela Ancuta
Abstract
The direct link between sustained type I interferon (IFN-I) signaling and HIV-1–induced immunopathogenesis during chronic infection remains unclear. Here we report studies using a monoclonal antibody to block IFN-α/β receptor 1 (IFNAR1) signaling during persistent HIV-1 infection in humanized mice (hu-mice). We discovered that, during chronic HIV-1 infection, IFNAR blockade increased viral replication, which was correlated with elevated T cell activation. Thus, IFN-Is suppress HIV-1 replication during the chronic phase but are not essential for HIV-1–induced aberrant immune activation. Surprisingly, IFNAR blockade rescued both total human T cell and HIV-specific T cell numbers despite elevated HIV-1 replication and immune activation. We showed that IFNAR blockade reduced HIV-1–induced apoptosis of CD4+ T cells. Importantly, IFNAR blockade also rescued the function of human T cells, including HIV-1–specific CD8+ and CD4+ T cells. We conclude that during persistent HIV-1 infection, IFN-Is suppress HIV-1 replication, but contribute to depletion and dysfunction of T cells.
Authors
Liang Cheng, Haisheng Yu, Guangming Li, Feng Li, Jianping Ma, Jingyun Li, Liqun Chi, Liguo Zhang, Lishan Su
Abstract
Humoral immunity is critical for viral control, but the identity and mechanisms regulating human antiviral B cells are unclear. Here, we characterized human B cells expressing T-bet and analyzed their dynamics during viral infections. T-bet+ B cells demonstrated an activated phenotype, a distinct transcriptional profile, and were enriched for expression of the antiviral immunoglobulin isotypes IgG1 and IgG3. T-bet+ B cells expanded following yellow fever virus and vaccinia virus vaccinations and also during early acute HIV infection. Viremic HIV-infected individuals maintained a large T-bet+ B cell population during chronic infection that was associated with increased serum and cell-associated IgG1 and IgG3 expression. The HIV gp140–specific B cell response was dominated by T-bet–expressing memory B cells, and we observed a concomitant biasing of gp140-specific serum immunoglobulin to the IgG1 isotype. These findings suggest that T-bet induction promotes antiviral immunoglobulin isotype switching and development of a distinct T-bet+ B cell subset that is maintained by viremia and coordinates the HIV Env–specific humoral response.
Authors
James J. Knox, Marcus Buggert, Lela Kardava, Kelly E. Seaton, Michael A. Eller, David H. Canaday, Merlin L. Robb, Mario A. Ostrowski, Steven G. Deeks, Mark K. Slifka, Georgia D. Tomaras, Susan Moir, M. Anthony Moody, Michael R. Betts
Abstract
HIV vaginal transmission accounts for the majority of newly acquired heterosexual infections. However, the mechanism by which HIV spreads from the initial site of viral entry at the mucosal surface of the female genital tract to establish a systemic infection of lymphoid and peripheral tissues is not known. Once the virus exits the mucosa it rapidly spreads to all tissues, leading to CD4+ T cell depletion and the establishment of a viral reservoir that cannot be eliminated with current treatments. Understanding the molecular and cellular requirements for viral dissemination from the genital tract is therefore of great importance, as it could reveal new strategies to lengthen the window of opportunity to target the virus at its entry site in the mucosa where it is the most vulnerable and thus prevent systemic infection. Using HIV vaginal infection of humanized mice as a model of heterosexual transmission, we demonstrate that blocking the ability of leukocytes to respond to chemoattractants prevented HIV from leaving the female genital tract. Furthermore, blocking lymphocyte egress from lymph nodes prevented viremia and infection of the gut. Leukocyte trafficking therefore plays a major role in viral dissemination, and targeting the chemoattractant molecules involved can prevent the establishment of a systemic infection.
Authors
Maud Deruaz, Thomas T. Murooka, Sophina Ji, Marc A. Gavin, Vladimir D. Vrbanac, Judy Lieberman, Andrew M. Tager, Thorsten R. Mempel, Andrew D. Luster
Abstract
The conditioning regimen used as part of the Berlin patient’s hematopoietic cell transplant likely contributed to his eradication of HIV infection. We studied the impact of conditioning in simian-human immunodeficiency virus–infected (SHIV-infected) macaques suppressed by combination antiretroviral therapy (cART). The conditioning regimen resulted in a dramatic, but incomplete depletion of CD4+ and CD8+ T cells and CD20+ B cells, increased T cell activation and exhaustion, and a significant loss of SHIV-specific Abs. The disrupted T cell homeostasis and markers of microbial translocation positively correlated with an increased viral rebound after cART interruption. Quantitative viral outgrowth and Tat/rev–induced limiting dilution assays showed that the size of the latent SHIV reservoir did not correlate with viral rebound. These findings identify perturbations of the immune system as a mechanism for the failure of autologous transplantation to eradicate HIV. Thus, transplantation strategies may be improved by incorporating immune modulators to prevent disrupted homeostasis, and gene therapy to protect transplanted cells.
Authors
Christopher W. Peterson, Clarisse Benne, Patricia Polacino, Jasbir Kaur, Cristina E. McAllister, Abdelali Filali-Mouhim, Willi Obenza, Tiffany A. Pecor, Meei-Li Huang, Audrey Baldessari, Robert D. Murnane, Ann E. Woolfrey, Keith R. Jerome, Shiu-Lok Hu, Nichole R. Klatt, Stephen DeRosa, Rafick P. Sékaly, Hans-Peter Kiem
Abstract
HIV-1 viremic controllers (VC) spontaneously control infection without antiretroviral treatment. Several studies indicate that IgG Abs from VCs induce enhanced responses from immune effector cells. Since signaling through Fc-γ receptors (FCGRs) modulate these Ab-driven responses, here we examine if enhanced FCGR activation is a common feature of IgG from VCs. Using an infected cell–based system, we observed that VC IgG stimulated greater FCGR2A and FCGR3A activation as compared with noncontrollers, independent of the magnitude of HIV-specific Ab binding or virus neutralization activities. Multivariate regression analysis showed that enhanced FCGR signaling was a significant predictor of VC status as compared with chronically infected patients (CIP) on highly active antiretroviral therapy (HAART). Unsupervised hierarchical clustering of patient IgG functions primarily grouped VC IgG profiles by enhanced FCGR2A, FCGR3A, or dual signaling activity. Our findings demonstrate that enhanced FCGR signaling is a common and significant predictive feature of VC IgG, with VCs displaying a distinct spectrum of FCGR activation profiles. Thus, profiling FCGR activation may provide a useful method for screening and distinguishing protective anti-HIV IgG responses in HIV-infected patients and in monitoring HIV vaccination regimens.
Authors
Raymond A. Alvarez, Ana M. Maestre, Kenneth Law, Natasha D. Durham, Maria Ines Barria, Akiko Ishii-Watabe, Minoru Tada, Manav Kapoor, Mathew T. Hotta, Gabriela Rodriguez-Caprio, Daniel S. Fierer, Ana Fernandez-Sesma, Viviana Simon, Benjamin K. Chen
Abstract
Flow cytometry is utilized extensively for cellular analysis, but technical limitations have prevented its routine application for characterizing virus. The recent introduction of nanoscale fluorescence-activated cytometric cell sorting now allows analysis of individual virions. Here, we demonstrate staining and sorting of infectious HIV. Fluorescent antibodies specific for cellular molecules found on budding virions were used to label CCR5-tropic Bal HIV and CXCR4-tropic NL4.3 HIV Env-expressing pseudovirions made in THP-1 cells (monocyte/macrophage) and H9 cells (T cells), respectively. Using a flow cytometer, we resolved the stained virus beyond isotype staining and demonstrated purity and infectivity of sorted virus populations on cells with the appropriate coreceptors. We subsequently sorted infectious simian/human immunodeficiency virus from archived plasma. Recovery was approximately 0.5%, but virus present in plasma was already bound to viral-specific IgG generated in vivo, likely contributing to the low yield. Importantly, using two broadly neutralizing HIV antibodies, PG9 and VRC01, we also sorted virus from archived human plasma and analyzed the sorted populations genetically and by proteomics, identifying the quasispecies present. The ability to sort infectious HIV from clinically relevant samples provides material for detailed molecular, genetic, and proteomic analyses applicable to future design of vaccine antigens and potential development of personalized treatment regimens.
Authors
Thomas Musich, Jennifer C. Jones, Brandon F. Keele, Lisa M. Miller Jenkins, Thorsten Demberg, Thomas S. Uldrick, Robert Yarchoan, Marjorie Robert-Guroff
Abstract
SIV DNA can be detected in lymphoid tissue–resident macrophages of chronically SIV-infected Asian macaques. These macrophages also contain evidence of recently phagocytosed SIV-infected CD4+ T cells. Here, we examine whether these macrophages contain replication-competent virus, whether viral DNA can be detected in tissue-resident macrophages from antiretroviral (ARV) therapy–treated animals and humans, and how the viral sequences amplified from macrophages and contemporaneous CD4+ T cells compare. In ARV-naive animals, we find that lymphoid tissue–resident macrophages contain replication-competent virus if they also contain viral DNA in ARV-naive Asian macaques. The genetic sequence of the virus within these macrophages is similar to those within CD4+ T cells from the same anatomic sites. In ARV-treated animals, we find that viral DNA can be amplified from lymphoid tissue–resident macrophages of SIV-infected Asian macaques that were treated with ARVs for at least 5 months, but we could not detect replication-competent virus from macrophages of animals treated with ARVs. Finally, we could not detect viral DNA in alveolar macrophages from HIV-infected individuals who received ARVs for 3 years and had undetectable viral loads. These data demonstrate that macrophages can contain replication-competent virus, but may not represent a significant reservoir for HIV in vivo.
Authors
Sarah R. DiNapoli, Alexandra M. Ortiz, Fan Wu, Kenta Matsuda, Homer L. Twigg III, Vanessa M. Hirsch, Kenneth Knox, Jason M. Brenchley
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