CROI 2016 Abstract eBook

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Poster Abstracts

257 Immunomodulatory Effects of Recreational Marijuana Use in Youth LivingWith HIV-1 Ashok Dinasarapu 1 ; Carla Mavian 2 ; Alberto Riva 2 ; Sofia Appelberg 3 ; JulieWilliams 2 ; John Sleasman 4 ; Maureen Goodenow 2 1 Emory Univ, Atlanta, GA, USA; 2 Univ of Florida, Gainesville, FL, USA; 3 Karolinska Inst, Stockholm, Sweden; 4 Duke Univ Sch of Med, Durham, NC, USA

Background: While the effects on human health by marijuana, a widely used recreational substance, remain debatable among the public and policymakers, therapeutic benefits for some conditions are recognized. Significant changes in gene expression in immune cells are associated with alcohol or tobacco use, but the combined effects are unknown. Our study was designed to explore the immunomodulatory effects of recreational marijuana use alone, or in combination with tobacco and alcohol, in HIV-infected young adults. Methods: Blood samples were collected in PaxGene tubes following IRBs protocols from a cross sectional cohort of HIV-seronegative [n=51] or HIV-infected, antiretroviral-treated [n=94] individuals with or without detectable viral loads [VL] matched for age [22 and 24 years, respectively] and demographics. Use of alcohol, marijuana or tobacco was assessed by self-reporting system and classified by frequency. Use of marijuana or tobacco was verified by plasma toxicology assays. RNA was amplified and hybridized to HG U133 Plus 2.0 Arrays. Raw probe signal values were normalized and differentially expressed genes were identified. Enrichment analysis was performed to identify the significance of regulated genes. Levels of secreted CXCL10 from THC-treated peripheral blood mononuclear cells (PBMC) were determined by ELISA. Results: Expression of almost 4000 genes differed between HIV-seronegative and HIV-seropositive individuals. Within the HIV-seropositive group, significant overlap of differentially expressed genes was found between triple substance use (VL≤50) and no-substance use (VL>50) groups, suggesting that multiple substance use and viremia modulate similar gene expression. Pathway analysis revealed that the cytokine-cytokine receptor pathway was enriched in the HIV- seropositive, non-substance use group (VL>50) compared to other groups. Marijuana use in subjects with VL≤50 led to enrichment in the MAPK-signaling pathway and to normalization of IL-15 and CXCL10 expression compared with seronegative non-substance users. The inhibitory properties of marijuana in vivo were supported by ex vivo studies where THC completely inhibited IFNβ- stimulated CXCL10 release from PBMC in a dose dependent manner. Conclusions: Recreational marijuana use normalized inflammatory and/or immune activation genes that were dysregulated even in virally suppressed HIV-infected individuals . Multi-substance use of marijuana with tobacco and alcohol reversed the immune suppression effects of marijuana alone. 258LB T Regulatory Cell Depletion in Controller Macaques Reactivates SIV and Boosts CTLs Cristian Apetrei ; Egidio Brocca-Cofano; Jennifer L. Stock; Benjamin B. Policicchio; HeTianyu; Kevin D. Raehtz; Cuiling Xu; Ivona Pandrea Univ of Pittsburgh, Pittsburgh, PA, USA Background: T regulatory cells (Tregs) may play a critical role in formation of the latent reservoir, as they are susceptible to HIV/SIV infection and resting Tregs harbor higher levels of HIV/SIV than the general quiescent CD4 + T cell population. During acute infection, Tregs decisively contribute to the establishment of HIV reservoir by reversing CD4 + T cell immune activation status. During chronic infection, they contribute to the impairment of CTL responses, as Treg expansion correlates with loss of CTL function and their ex vivo depletion enhances T cell responses to HIV/SIV antigens. HLAB27 + and B57 + HIV-specific CD8 + T cells from elite controllers evade Treg suppression. As such, we hypothesized that Treg depletion is a valid approach for HIV cure, in which a single intervention reduces the size of the reservoir, reactivates the virus and boosts cell-mediated immune responses. Methods: Two SIVsab-infected RMs, in which spontaneous supercontrol of virus replication (<3 copies/ml plasma) associates complete control of immune activation, were depleted of Tregs by administration of Ontak (Denileukin diftitox), an engineered protein combining IL-2 and diphtheria toxin. Treg depletion was monitored by flow cytometry and immunohistochemistry; plasma viral load was measured by single copy assay; specific cellular immune responses to SIV antigens were monitored flow-cytometrically by intracellular cytokine staining after stimulation with SIVsab peptides. Results: Ontak administration to SIVsab-infected RMs resulted in significant depletion (>75%) of the circulating Fox-P3 + CD25 + CD4 + T cells. Up to 60% and >50% of Tregs were depleted from gut and the lymph nodes, respectively. Ontak impact on overall CD8 + T cell counts was minimal. Treg depletion resulted in a major increase of the levels of CD4 + T cell activation (Ki-67). In the absence of antiretroviral therapy, virus rebound to 10 3 vRNA copies/ml of plasma occurred after Ontak administration. Importantly, Treg depletion resulted in a significant boost of the SIV-specific CD8 + T cells and rapid clearance of the reactivated virus. Conclusions: Treg depletion in chronically SIV-infected superelite controller RMs resulted in both reactivation of latent virus and a boost of CTL responses. The overall Treg ability to control immune responses was significantly impaired despite the fact that Treg depletion was incomplete. As no latency reversing agent in development has such a dual activity, our strategy holds great promises for cure research. 259LB Increased Effector CD8 Lymphocyte Trafficking to Lymph Nodes Induced by hetIL-15 George N. Pavlakis 1 ; AntonioValentin 1 ; Cristina K. Bergamaschi 1 ; Dionysios K.Watson 1 ; Costantinos Petrovas 2 ; Xintao K. Hu 1 ; James I. Mullins 3 ; Barbara K. Felber 4 1 NCI at Frederick, Frederick, MD, USA; 2 NIH, Bethesda, MD, USA; 3 Univ of Washington, Seattle, WA, USA; 4 NCI, Rockville, MD, USA Background: IL-15 stimulates the growth activation and tissue dissemination of NK cells and cytotoxic lymphocytes. We have produced and characterized heterodimeric IL-15 (hetIL-15), the authentic form of IL-15 found in the circulation. This formulation is in clinical trials for cancer. Methods: hetIL-15 was purified and its pharmacokinetic and pharmacodynamic properties were evaluated in macaques upon SC administration. Phenotype and functional changes in lymphocyte subsets were monitored by flow cytometry and multiplexed confocal imaging (MCI). Results: Treatment of SIV or SHIV infected macaques with hetIL-15 resulted in a significant increase of circulating CD8+ effector T cells and NK cells with activated cytotoxic phenotype (Granzyme + ). This expanded T lymphocyte population was disseminated to effector sites, and was also present in secondary lymphoid organs where an increased frequency of total CD8 and of Ag-specific effector CD8 T cells could be observed by flow cytometry and imaging (MCI). A subset of CD8 T cells present in lymph nodes expresses CXCR5, indicating ability to migrate into germinal centers where chronically infected CD4 + Tfh reside. MCI confirmed the presence of effector CD8 cells in germinal centers and showed that these cells are cytotoxic (GrzmB + ) and actively proliferating (Ki67 + ) in response to hetIL-15. These results strongly suggest the use of hetIL-15 in chronic HIV/SIV infection. An exciting possibility is the augmentation of immune responses in the areas of residual HIV/SIV persistence, and the combination with therapeutic vaccination, which has resulted in promising reduction in chronic viremia. We test new generation of therapeutic vaccines focusing immune responses on the conserved regions of HIV/SIV in combination with hetIL-15 in an effort to amplify novel cytotoxic responses with no possibility of immune escape. Conclusions: We explore the potential of IL-15 as a viral reservoir reducing agent in ART-treated SIV infected macaques. hetIL-15 treatment enhances the number, activation and cytotolytic potential of CD8 cells in LN and germinal centers, a known site of virus persistence. hetIL-15 treatment in combination with pDNA vaccine targeting the “Achilles’ heel” of the virus, i.e., the highly conserved regions (CE), in virus sanctuary areas (germinal centers) is a promising HIV eradication strategy. 260 Distinct Gut Microbiota Composition in Gay Men Muntsa Rocafort 1 ; Marc Noguera-Julian 1 ;Yolanda Guillen 2 ; Mariona Parera 1 ; Piotr Nowak 3 ; Falk Hildebrand 4 ; Georg Zeller 4 ; Anders Sönnerborg 3 ; Peer Bork 4 ; Roger Paredes 1 1 IrsiCaixa Inst for AIDS Rsr, Badalona, Spain; 2 IrsiCaixa Inst for AIDS Rsr, Barcelona, Spain; 3 Karolinska Inst, Stockholm, Sweden; 4 Structural and Computational Biology, European Molecular Biology Lab, Heidelberg, Germany Background: The precise effects of HIV-1 on the human microbiome are unclear. Initial cross-sectional studies provided contradictory associations between microbial richness and HIV status and suggested shifts from Bacteroides to Prevotella predominance following HIV-1 infection, which have not been found in animal models or in studies matched for HIV-1 risk groups.

Poster Abstracts

100

CROI 2016