CROI 2016 Abstract eBook

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Poster Abstracts

Methods: Peripheral blood was collected from HIV acute seroconverters (n=12), ART- (n=145), ART+ (n=23), elite controllers (n=12), and 51 healthy controls from sites in Africa, Europe, Asia, and USA. Multi-parametric flow cytometry was used to assess T-bet, Eomes, maturation, activation, exhaustion, Gag-p24, and cytokine/chemokine expression in bulk and antigen-specific CD4+ T cells. Data were acquired by flow cytometry and analyses performed in FlowJo, GraphPad Prism, R and SPICE. Results: We find in HIV-seronegative subjects that CD4+ T cell expression of T-bet and Eomes is associated with effector differentiation, cytolytic potential, and preferential CCR5 expression. However, T-bet+Eomes+memory CD4+ T cells are preserved in both HIV-1 and HIV-2 infected individuals, despite increased immune activation, exhaustion and senescence compared to total CD4+ T cells. In contrast, HIV-1-specific CD4+ T cells selectively lose T-bet expression following the resolution of acute viremia and do not reacquire T-bet expression into chronic infection or post-ART. Preserved levels of T-bet+Eomes+ CD4+ T cells are also found in individuals with high HIV-1 viremia, and these cells demonstrate low susceptibility to HIV-1 infection in vitro . Finally, we show that T-bet+Eomes+ CD4+ T cells are the superior producers of β-chemokines and possess lower CCR5 expression directly ex vivo in HIV-1 infected subjects. Conclusions: Memory CD4+ T cells expressing T-bet and Eomes are preserved in HIV infection, probably through the influence of increased β-chemokine production and lower CCR5 expression prohibiting HIV susceptibility. Conversely, lack of T-bet and Eomes expression in HIV-specific CD4+ T cells provides a potential mechanism of increased susceptibility for HIV infection. 255 Antioxidants Improve Lung Immunity and T-Cell Proliferation in Immune Non-Responders Sushma K. Cribbs 1 ; Lou Ann Brown 1 ; Mirko Paiardini 2 ; Colleen Kraft 1 ; David Rimland 1 ; Jeffrey L. Lennox 1 ;Vincent C. Marconi 1 ; David Guidot 1 1 Emory Univ Sch of Med, Atlanta, GA, USA; 2 Yerkes Natl Primate Rsr Cntr, Emory Univ, Atlanta, GA, USA Background: HIV-1 immune non-responders are at increased risk for lung infections. Alveolar macrophages express CXCR4 and CCR5 and can be infected by HIV-1. We have previously shown that HIV replication within alveolar macrophages impairs phagocytic function, that HIV-1-infected individuals may have zinc and glutathione deficiency leading to oxidative stress, and that in vitro supplementation of zinc and glutathione improves phagocytic function. We hypothesize that dietary zinc and thiol antioxidant S-adenosylmethionine supplementation will enhance alveolar macrophage immune function and reduce macrophage viral burden in immune non-responders. Methods: In a prospective cohort study non-smoking, HIV-1 infected immune non-responders were given zinc 30 mg and S-adenosylmethionine 1600 mg daily. All subjects underwent bronchoalveolar lavage and blood sampling pre-treatment and after 12 months on therapy. Alveolar macrophage phagocytic index [(% positive cells x mean channel fluorescence)/100] was measured by flow cytometry using FITC-labeled S. aureus . Proviral DNA was qualitatively measured using a modified version of the Abbott RealTime HIV-1 Assay (Abbott Molecular Inc. Des Plaines, IL). Immunologic parameters, including levels of CD4 and CD8 T cells, their main differentiation subsets, and their levels of proliferation were analyzed by flow cytometry. Results: We enrolled 14 HIV-1 infected subjects (median CD4 count=257/μl), all of whom had blood HIV-1 RNA below level of detection on standard commercial assays. Alveolar macrophage phagocytosis increased significantly with treatment (31.4%+ 43.9, p=0.02). There was no significant change in lavage glutathione levels. HIV-1 proviral DNA was detected in 5/14 patients initially and all were negative after treatment. There were no significant changes in the frequencies of CD4 and CD8 T cells or their main maturation subsets and no significant changes on the frequencies of CD4 and CD8 T cells expressing activation markers (HLA-DR and CD38). However, there was a significant reduction in the frequencies of CD4 (p<0.001) and CD8 (p=0.04) T-cell proliferation, as assessed by Ki-67 expression. Conclusions: In HIV-1 infected immune non-responders on antiretroviral therapy, dietary supplementation with zinc and S-adenoslymethionine reduced T cell proliferation, improved alveolar macrophage phagocytosis and may improve HIV-1 clearance from the lung, potentially reducing the risk for lung infections. 256 The Effect of KIR-Mediated Immunity on HIV Clinical Outcome in South Africa Masahiko Mori 1 ; Ellen M. Leitman 1 ; Bruce D.Walker 2 ;Thumbi P. Ndungu 3 ; Philip Goulder 1 1 Univ of Oxford, Oxford, UK; 2 Ragon Inst of MGH, MIT, and Harvard, Cambridge, MA, USA; 3 Univ of KwaZulu-Natal, Durban, South Africa Background: HLA Class I molecules contribute to the immune control of HIV through antigen presentation to both CTLs and NK cells. CTL-mediated HIV control through antigen presentation by protective HLA alleles (eg HLA-B*27/57/58:01) is well documented. The role of NK cell response is also well described, with the protective effects of HLA-Bw4 alleles in combination with, killer immunoglobulin-like receptor (KIR) 3DL1 and 3DS.,Studies of the role of KIR2D-HLA-C in HIV control, however, remain sparse. Methods: 327 HIV-infected treatment-naïve patients were recruited from South Africa, and the effects of HLA-KIR interactions on clinical outcome were analyzed. Results: Viral setpoint in subjects with KIR2DL3 was significantly higher than in those without it (median 4.6 vs 4.3 log 10 copies/ml, p=0.02). This difference in viral setpoint between KIR2DL3-positive vs KIR2DL3-negative individuals was significant (median 5.0 vs 3.4 log 10 copies/ml, p=0.04) only among subjects expressing HLA-C*16, a member of the HLA-C1 group and a ligand of KIR2DL3, but not among subjects with other HLA alleles in the HLA-C1 group. Subjects expressing alleles from the HLA-C1 group also showed significant viral setpoint differences when they co-expressed KIR2DL3 (p=0.01), but not other receptors of HLA-C1 group (KIR2DL2 or KIR2DS2), suggesting some combinations of HLA-C1 alleles and KIR2DL3 may drive changes in viremia despite sharing the same HLA-KIR ligand-receptor structures. Longitudinal analysis of 303 patients showed more frequent ART initiation among subjects with HLA-C*16+KIR2DL3+ combination than in subjects without it (p=0.01, Figure). The more frequent ART initiation in HLA- C*16+KIR2DL3+ individuals remained significant in multivariate analysis (aHR 2.5, 95% CI 1.2-5.1, p=0.01) and this was independent of other combinations of HLA-C1 alleles and KIR2DL3. Finally, no benefit of KIR3DL1/S1-HLA-Bw4 combination on clinical outcome was observed in this cohort. Conclusions: In this study, the deleterious effects of KIR2DL3, particularly in combination with its ligand HLA-C*16, on clinical outcome among HIV-infected South African individuals were identified. These findings highlight the existence of unique anti-HIV innate immune pressures and viral adaptation to this pressure specific to each endemic area.

Poster Abstracts

99

CROI 2016