AIDS/HIV
Abstract
Current strategies aimed to cure HIV infection are based on combined efforts to reactivate the virus from latency and improve immune effector cell function to clear infected cells. These strategies are primarily focused on CD8+ T cells and approaches are challenging due to insufficient HIV antigen production from infected cells and poor HIV-specific CD8+ T cells. γδ T cells represent a unique subset of effector T cells that can traffic to tissues, and selectively target cancer or virally infected cells without requiring MHC presentation. We analyzed whether γδ T cells represent a complementary/alternative immunotherapeutic approach towards HIV cure strategies. γδ T cells from HIV-infected virologically suppressed donors were expanded with bisphosphonate pamidronate (PAM) and cells were used in autologous cellular systems ex vivo. These cells (a) are potent cytotoxic effectors able to efficiently inhibit HIV replication ex vivo, (b) degranulate in the presence of autologous infected CD4+ T cells, and (c) specifically clear latently infected cells after latency reversal with vorinostat. This is the first proof of concept to our knowledge showing that γδ T cells target and clear autologous HIV reservoirs upon latency reversal. Our results open potentially new insights into the immunotherapeutic use of γδ T cells for current interventions in HIV eradication strategies.
Authors
Carolina Garrido, Matthew L. Clohosey, Chloe P. Whitworth, Michael Hudgens, David M. Margolis, Natalia Soriano-Sarabia
Abstract
Estimating the size of the viral reservoir is critical for HIV cure strategies. Biomarkers in peripheral circulation may give insights into the establishment of the viral reservoir in compartments not easily accessible. We therefore measured systemic levels of 84 soluble biomarkers belonging to a broad array of immune pathways in acute HIV infection in both antiretroviral therapy–naive (ART-naive) individuals as well as individuals who began ART upon early detection of HIV infection. These biomarkers were measured longitudinally during acute and chronic infection and their relationship to viral reservoir establishment and persistence was assessed. We observed several distinct biomarker pathways induced following HIV infection such as IFN-γ–signaled chemokines, proinflammatory markers, and TNF-α–family members. Levels of several of these factors directly correlated with contemporaneous viral loads and/or frequency of peripheral blood mononuclear cells harboring HIV DNA during acute HIV infection. MCP-1, MIP-3β, sTNFR-II, and IL-10 levels prior to ART associated with HIV DNA levels after 96 weeks of treatment, suggesting a link between early immune signaling events and the establishment and persistence of the viral reservoir during ART. Furthermore, they offer potentially novel tools for gaining insight into relative reservoir size in acutely infected individuals and the potential of associated risks of treatment interruption.
Authors
Jeffrey E. Teigler, Louise Leyre, Nicolas Chomont, Bonnie Slike, Ningbo Jian, Michael A. Eller, Nittaya Phanuphak, Eugène Kroon, Suteeraporn Pinyakorn, Leigh Anne Eller, Merlin L. Robb, Jintanat Ananworanich, Nelson L. Michael, Hendrik Streeck, Shelly J. Krebs, RV254/RV217 study groups
Abstract
Replication competent HIV-1 persists in a subpopulation of CD4+ T lymphocytes despite prolonged antiretroviral treatment. This residual reservoir of infected cells harbors transcriptionally silent provirus capable of reigniting productive infection upon discontinuation of antiretroviral therapy. Certain classes of drugs can activate latent virus but not at levels that lead to reductions in HIV-1 reservoir size in vivo. Here, we show the utility of CD4+ receptor targeting exosomes as an HIV-1 latency reversal agent (LRA). We engineered human cellular exosomes to express HIV-1 Tat, a protein that is a potent transactivator of viral transcription. Preparations of exosomal Tat-activated HIV-1 in primary, resting CD4+ T lymphocytes isolated from antiretroviral-treated individuals with prolonged periods of viral suppression and led to the production of replication competent HIV-1. Furthermore, exosomal Tat increased the potency of selected LRA by over 30-fold in terms of HIV-1 mRNA expression, thereby establishing it as a potentially new class of biologic product with possible combinatorial utility in targeting latent HIV-1.
Authors
Xiaoli Tang, Huafei Lu, Mark Dooner, Stacey Chapman, Peter J. Quesenberry, Bharat Ramratnam
Abstract
Major advances in donor identification, antigen probe design, and experimental methods to clone pathogen-specific antibodies have led to an exponential growth in the number of newly characterized broadly neutralizing antibodies (bnAbs) that recognize the HIV-1 envelope glycoprotein. Characterization of these bnAbs has defined new epitopes and novel modes of recognition that can result in potent neutralization of HIV-1. However, the translation of envelope recognition profiles in biophysical assays into an understanding of in vivo activity has lagged behind, and identification of subjects and mAbs with potent antiviral activity has remained reliant on empirical evaluation of neutralization potency and breadth. To begin to address this discrepancy between recombinant protein recognition and virus neutralization, we studied the fine epitope specificity of a panel of CD4-binding site (CD4bs) antibodies to define the molecular recognition features of functionally potent humoral responses targeting the HIV-1 envelope site bound by CD4. Whereas previous studies have used neutralization data and machine-learning methods to provide epitope maps, here, this approach was reversed, demonstrating that simple binding assays of fine epitope specificity can prospectively identify broadly neutralizing CD4bs–specific mAbs. Building on this result, we show that epitope mapping and prediction of neutralization breadth can also be accomplished in the assessment of polyclonal serum responses. Thus, this study identifies a set of CD4bs bnAb signature amino acid residues and demonstrates that sensitivity to mutations at signature positions is sufficient to predict neutralization breadth of polyclonal sera with a high degree of accuracy across cohorts and across clades.
Authors
Hao D. Cheng, Sebastian K. Grimm, Morgan S.A. Gilman, Luc Christian Gwom, Devin Sok, Christopher Sundling, Gina Donofrio, Gunilla B. Karlsson Hedestam, Mattia Bonsignori, Barton F. Haynes, Timothy P. Lahey, Isaac Maro, C. Fordham von Reyn, Miroslaw K. Gorny, Susan Zolla-Pazner, Bruce D. Walker, Galit Alter, Dennis R. Burton, Merlin L. Robb, Shelly J. Krebs, Michael S. Seaman, Chris Bailey-Kellogg, Margaret E. Ackerman
Abstract
Accurate HIV-1 incidence estimation is critical to the success of HIV-1 prevention strategies. Current assays are limited by high false recent rates (FRRs) in certain populations and a short mean duration of recent infection (MDRI). Dynamic early HIV-1 antibody response kinetics were harnessed to identify biomarkers for improved incidence assays. We conducted retrospective analyses on circulating antibodies from known recent and longstanding infections and evaluated binding and avidity measurements of Env and non-Env antigens and multiple antibody forms (i.e., IgG, IgA, IgG3, IgG4, dIgA, and IgM) in a diverse panel of 164 HIV-1–infected participants (clades A, B, C). Discriminant function analysis identified an optimal set of measurements that were subsequently evaluated in a 324-specimen blinded biomarker validation panel. These biomarkers included clade C gp140 IgG3, transmitted/founder clade C gp140 IgG4 avidity, clade B gp140 IgG4 avidity, and gp41 immunodominant region IgG avidity. MDRI was estimated at 215 day or alternatively, 267 days. FRRs in untreated and treated subjects were 5.0% and 3.6%, respectively. Thus, computational analysis of dynamic HIV-1 antibody isotype and antigen interactions during infection enabled design of a promising HIV-1 recency assay for improved cross-sectional incidence estimation.
Authors
Kelly E. Seaton, Nathan A. Vandergrift, Aaron W. Deal, Wes Rountree, John Bainbridge, Eduard Grebe, David A. Anderson, Sheetal Sawant, Xiaoying Shen, Nicole L. Yates, Thomas N. Denny, Hua-Xin Liao, Barton F. Haynes, Merlin L. Robb, Neil Parkin, Breno R. Santos, Nigel Garrett, Matthew A. Price, Denise Naniche, Ann C. Duerr, The CEPHIA group, Sheila Keating, Dylan Hampton, Shelley Facente, Kara Marson, Alex Welte, Christopher D. Pilcher, Myron S. Cohen, Georgia D. Tomaras
Abstract
IL-7 regulates homeostatic mechanisms that maintain the overall size of the T cell pool throughout life. We show that, under steady-state conditions, IL-7 signaling is principally mediated by activation of signal transducers and activators of transcription 5 (STAT5). In contrast, under lymphopenic conditions, there is a modulation of STAT1 expression resulting in an IL-7–dependent STAT1 and STAT5 activation. Consequently, the IL-7–induced transcriptome is altered with enrichment of IFN-stimulated genes (ISGs). Moreover, STAT1 overexpression was associated with reduced survival in CD4+ T cells undergoing lymphopenia-induced proliferation (LIP). We propose a model in which T cells undergoing LIP upregulate STAT1 protein, “switching on” an alternate IL-7–dependent program. This mechanism could be a physiological process to regulate the expansion and size of the CD4+ T cell pool. During HIV infection, the virus could exploit this pathway, leading to the homeostatic dysregulation of the T cell pools observed in these patients.
Authors
Cecile Le Saout, Megan A. Luckey, Alejandro V. Villarino, Mindy Smith, Rebecca B. Hasley, Timothy G. Myers, Hiromi Imamichi, Jung-Hyun Park, John J. O’Shea, H. Clifford Lane, Marta Catalfamo
Abstract
Biological aging is associated with immune activation (IA) and declining immunity due to systemic inflammation. It is widely accepted that HIV infection causes persistent IA and premature immune senescence despite effective antiretroviral therapy and virologic suppression; however, the effects of combined HIV infection and aging are not well defined. Here, we assessed the relationship between markers of IA and inflammation during biological aging in HIV-infected and -uninfected populations. Antibody response to seasonal influenza vaccination was implemented as a measure of immune competence and relationships between IA, inflammation, and antibody responses were explored using statistical modeling appropriate for integrating high-dimensional data sets. Our results show that markers of IA, such as coexpression of HLA antigen D related (HLA-DR) and CD38 on CD4+ T cells, exhibit strong associations with HIV infection but not with biological age. Certain variables that showed a strong relationship with aging, such as declining naive and CD38+ CD4 and CD8+ T cells, did so regardless of HIV infection. Interestingly, the variable of biological age was not identified in a predictive model as significantly impacting vaccine responses in either group, while distinct IA and inflammatory variables were closely associated with vaccine response in HIV-infected and -uninfected populations. These findings shed light on the most relevant and persistent immune defects during virological suppression with antiretroviral therapy.
Authors
Lesley R. de Armas, Suresh Pallikkuth, Varghese George, Stefano Rinaldi, Rajendra Pahwa, Kristopher L. Arheart, Savita Pahwa
Abstract
BACKGROUND. HIV-infected individuals, even well controlled with combined antiretroviral therapy (cART), have systemic inflammation and comorbidities. Substance P (SP) is an undecapeptide, which mediates neurotransmission and inflammation through its cognate neurokinin 1 receptor (NK1R). Plasma SP levels are elevated in HIV-infected individuals. The FDA-approved antiemetic aprepitant, an NK1R antagonist, has anti-HIV effects and antiinflammatory actions. We evaluated the safety, pharmacokinetics, and antiinflammatory properties of aprepitant in HIV-positive individuals receiving cART. METHODS. We conducted a phase 1B study of 12 HIV-positive individuals on a ritonavir-containing regimen (HIV viral load less than 40 copies/ml and CD4 > 400 cells/μl). Participants received open-label aprepitant 375 mg per day for 28 days and were followed for an additional 30 days. Changes in plasma levels of proinflammatory markers were assessed using flow cytometry, ELISA, luminex, and SOMAscan assays. RESULTS. The mean peak aprepitant plasma concentration was 30.7 ± 15.3 μg/ml at day 14 and 23.3 ± 12.3 μg/ml at day 28. Aprepitant treatment resulted in decreased plasma SP levels and affected 176 plasma proteins (56 after FDR) and several metabolic pathways, including inflammation and lipid metabolism. No change in soluble CD163 was observed. Aprepitant treatment was associated with a moderate increases in total and HDL cholesterol and affected select hematologic and metabolic markers, which returned to baseline levels 30 days after aprepitant treatment was stopped. There were 12 mild and 10 moderate adverse events (AE). CONCLUSIONS. Aprepitant is safe and well tolerated. The antiinflammatory properties of aprepitant make it a possible adjunctive therapy for comorbid conditions associated with HIV infection. TRIAL REGISTRATION. ClinicalTrials.gov (NCT02154360). FUNDING. This research was funded by NIH UO1 MH090325, P30 MH097488, and PO1 MH105303.
Authors
Sergei Spitsin, Pablo Tebas, Jeffrey S. Barrett, Vasiliki Pappa, Deborah Kim, Deanne Taylor, Dwight L. Evans, Steven D. Douglas
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
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