CROI 2020 Abstract eBook

Abstract eBook

Poster Abstracts

196 ABNORMAL IMMUNOMETABOLISM AND GENE ACCESSIBILITY IN ALVEOLAR MACROPHAGES IN HIV Sara C. Auld 1 , Jolyn Fernandes 1 , Mariam Ahmed 1 , Neel R. Gandhi 1 , Samantha Yeligar 1 , Bashar Staitieh 1 1 Emory University, Atlanta, GA, USA Background: People with HIV, including those who are on antiretroviral therapy (ART) with an undetectable viral load, have an elevated risk of infectious and non-infectious pulmonary diseases, which persist even after immune reconstitution with ART. In the setting of HIV, alveolar macrophages serve as a viral reservoir and exhibit derangements in antioxidant balance and innate immune function. We sought to determine whether alterations in immunometabolism, which have been implicated in other pulmonary diseases, were associated with these observed immune defects in alveolar macrophages of people with HIV. Methods: We enrolled 10 participants for a research bronchoscopy study in Atlanta, GA. Five participants with HIV were matched by age, sex, race and smoking status with five participants without HIV. Participants had no major medical comorbidities and those with HIV were on ART for ≥ 18 months with a CD4 count ≥ 350 cells/μl and undetectable viral load. Bronchoalveolar lavage was performed and alveolar macrophages were washed and isolated before plating for analysis of mitochondrial bioenergetics using Agilent Seahorse XFe96 and chromatin accessibility using ATAC-seq. Results: Compared to participants without HIV, participants with well- controlled HIV demonstrated impaired alveolar macrophage oxygen consumption rates and mitochondrial bioenergetics across multiple domains, including basal and ATP-linked respiration (Figure). In parallel, ATAC-seq analysis identified 803 genes with significantly greater chromatin accessibility in participants with HIV than in those without HIV. Of those genes, 19 are known to have a critical impact on mitochondrial homeostasis, with functions ranging frommitochondrial RNA processing to free radical scavenging, including mitochondrial transcription termination factor-4 (MTERF4), superoxide dismutase 2 (SOD2), cathepsin B (CTSB), and Methionyl-TRNA Synthetase 2 (MARS2). Conclusion: In people with HIV, we identified alterations in alveolar macrophage mitochondrial bioenergetics and chromatin accessibility for multiple genes associated with mitochondrial function. These alterations in alveolar macrophage function, in the face of ART and immune reconstitution, suggest that mitochondrial derangements may contribute to the elevated risk of pulmonary disease among people with HIV.

infection with a cocktail of antiretroviral drugs. Furthermore, 5 RMs after ART interruption (8 weeks post-ART initiation) and 4 untreated chronically infected were also studied. Peripheral blood and mechanically isolated cells fromMLNs were analyzed by flow cytometry. Results: Acute SIV infection was associated with decreased CD4/CD8 ratio and increased memory CD8 T-cell immune-activation (CD39/HLA-DR), exhaustion (PD1) and immunosuppressive CTLA-4 expression in both blood and MLNs which were all normalized by early ART initiation. Notably, MLN CD8 T-cells had consistently higher levels of immunosuppressive CTLA-4 and CD39 expression compared to matched blood samples in acute phase. Furthermore, acute SIV infection resulted in the expansion of FoxP3+ CD8 Tregs in both blood and MLNs, while early ART decreased CD8 Tregs only in blood. Helios+ thymic CD8 Tregs were also increased in both tissues in acute infection which were normalized by ART. Analyzing the trafficking of CD8 T-cells by assessing the expression of chemokine receptors, we found that the acute SIV infection results in decreased of CCR6+ but not CXCR3-expressing CD8 T-cells in both MLNs and blood, which was recovered following early ART. ART interruption was associated with increased HLA-DR+ CD8 T-cells and decreased CCR6+ CD8 T-cells within MLNs. Conclusion: Early ART initiation during acute infection normalized CD8 frequencies and their markers of immune activation and function in both MLNs and blood, but elevated levels of suppressive CD8 Tregs persists despite early ART in MLNs. This could be of great importance regarding immune surveillance of SIV persistence despite ART. 198 ENHANCED MUCOSAL IMMUNITY AND SIV SUPPRESSION AFTER MESENCHYMAL STEM-CELL TRANSFER Mariana Guedes Weber 1 , Lauren Hirao 1 , Abigail Mende 1 , Clarissa Rocha 1 , Joy E. Walters 1 , Juan Arredondo 1 , Bipin Balan 2 , Sonny Elizaldi 1 , Smita Iyer 1 , Alice Tarantal 1 , Amir Kol 1 , Satya Dandekar 1 1 University of California Davis, Davis, CA, USA, 2 University of Palermo, Palermo, Italy Background: Despite the presence of HIV-specific responses, HIV reservoirs persist and pose obstacles for cure. Early pathogenic effects of HIV infection in secondary lymphoid tissues including the gut contribute to ineffective anti-viral immunity, which are not repaired by ART. MSC secrete immuno-modulatory molecules and have beneficial effects in clinical studies. Using the SIV model of AIDS, we tested the hypothesis that systemic MSC administration will modulate antigen presentation and enhance anti-viral immunity at mucosal sites and lead to better viral suppression and increased immune recovery. Methods: Rhesus macaques with chronic SIV infection were administered with MSC by adoptive transfer and compared with SIV-infected and SIV-negative animals without MSC treatment. Virologic, immunologic, transcriptomic, metabolomic and microbiota (16s sequencing) analyses were performed. SIV RNA loads in plasma and tissue samples were determined by RTPCR and RNAscope. Changes in the T and B cell subset distribution and activation was measured by flow cytometry. SIV-specific cellular and humoral (SIV Env antibodies by ELISA) responses were measured and changes in the gene expression (RNAseq) were performed. Results: MSC-treated animals had decreased SIV viral loads that correlated with increased levels of activated B cells, SIV-specific CD8+ T cells and SIV Env-specific antibodies in peripheral blood compared to untreated controls. In the gut and lymph nodes, SIV RNA-positive cells were relocated to germinal centers and majority of themwere PD1+. In contrast, SIV+ cells were dispersed in lamina propria. Transcriptomic analysis revealed enhanced immune networks supporting anti-viral immunity. Increased prevalence of Lactobacillus and enhanced Linoleic acid metabolismwas detected. Conclusion: Collectively, our data support the hypothesis that MSCs enhance the virus-specific cellular and humoral immune responses by corralling SIV+ cells to the lymphoid follicles and improving antigen presentation and activating immune cell networks. Thus, MSC can be used for reviving or tooling mucosal immunity in HIV infection for viral clearance. 199 IDENTIFYING CENTRAL COMPONENTS OF THE HIV-1+ PREGNANCY IMMUNE NETWORK Alexander Cocker 1 , Sarah Dermont 2 , Waheed Khan 2 , Nesrina Imami 1 , Mark Johnson 1 1 Imperial College London, London, UK, 2 Chelsea and Westminster Hospital, London, UK

Poster Abstracts

197 IMPACT OF EARLY ART ON CD8 T CELLS IN MESENTERIC LYMPH NODES DURING SIV INFECTION Alexis Yero 1 , Omar Farnos 1 , Henintsoa Rabezanahary 2 , Ghita Benmadid- Laktout 2 , Julien Clain 2 , Gina Racine 2 , Jerome Estaquier 2 , Mohammad-Ali Jenabian 1 1 Université du Québec à Montréal, Montreal, QC, Canada, 2 CHU de Québec- Université Laval, Quebec, QC, Canada Background: CD8 T-cells play a pivotal role in clearance of HIV-infected cells, such that CD8 exhaustion contributes to their dysfunction and consequently, viral persistence. Mesenteric lymph nodes (MLNs), which drain the large and small intestine, are critical sites for the induction and maintenance of gut mucosal immunity. However, the dynamics of CD8 T-cells in MLNs is less known due to the lack of accessibility to these tissues in human. Thus, we assessed CD8 T-cell dynamics in MLNs vs blood in SIV-infected rhesus macaques (RMs) following early antiretroviral therapy (ART) initiation. Methods: 32 female Chinese RMs were enrolled including 25 intravenously SIVmac251-infected animals. Nine monkeys were treated at day 4 post-

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CROI 2020