CROI 2019 Abstract eBook

Abstract eBook

Oral Abstracts

significant (p=0.01), one-week delay in SIV rebound. The impact of ICB on the size of the reservoir during ART is under investigation. Conclusion: PD-1/CTLA-4 dual blockade was well tolerated in ART-suppressed, SIV-infected RMs, and was pharmacologically active as demonstrated by the expansion of effector T-cells in PB. This effect was coupled to a synergistic and potent activity in increasing SIV RNA in plasma, suggesting checkpoint blockade may facilitate viral induction and improve T-cell function.

induced a transient increase in the frequencies of cycling T cells (expressing Ki-67) in blood of ART-treated, SIV-infected RMs (p<0.05). Furthermore, FTY720 promoted an increase in the number of T cells retained in LN (p=0.01), as determined directly in situ by histocytometry. Notably, the FTY720-induced inhibition of T cell egress from LN resulted in a measurable decrease of SIV-DNA and -RNA content in LN Tfh cells in most treated animals as measured by RNAscope (p=0.02; n=6) and qPCR (p=0.04; group 2). Conclusion: By retaining cytolytic T cells in lymphoid sites of SIV persistence, FTY720 administration has the potential to limit a critical cellular reservoir of Tfh cells. As such, FTY720 should be considered in combined immune based interventions aimed at HIV remission. 134 TRANSCRIPTIONAL SIGNATURE OF LYMPH NODE CD8+ T CELLS IN HIV ELITE CONTROLLERS Son Nguyen 1 , Claire Deleage 2 , Sam Darko 3 , Amy Ransier 3 , Duc P. Truong 4 , Divyansh Argawal 1 , Alberto Sada Japp 1 , Perla Del Río-Estrada 5 , Ali Naji 6 , Gustavo Reyes-Terán 5 , Jacob D. Estes 7 , Daniel Douek 3 , Steven G. Deeks 8 , Marcus Buggert 9 , Michael R. Betts 1 1 University of Pennsylvania, Philadelphia, PA, USA, 2 National Cancer Institute, Frederick, MD, USA, 3 NIH, Bethesda, MD, USA, 4 Southern Methodist University, Dallas, TX, USA, 5 National Institute of Respiratory Diseases, Mexico City, Mexico, 6 Hospital of the University of Pennsylvania, Philadelphia, PA, USA, 7 Oregon Health and Sciences University, Portland, OR, USA, 8 University of California San Francisco, San Francisco, CA, USA, 9 Karolinska Institute, Stockholm, Sweden Background: Extensive evidence has indicated that peripheral blood HIV- specific CD8+ T cell cytolytic activity and effector functions are associated with the control of HIV replication in HIV elite controllers (EC). However, the majority of HIV replication in EC likely occurs in lymphoid tissue, where CD8+ T cell immune surveillance mechanisms are undefined. Here we performed single-cell RNA sequencing (scRNAseq) analyses to determine the transcriptional signature of HIV-specific CD8+ T cells that control viral replication in lymphoid tissue of EC. Methods: We isolated human lymph node (LN) mononuclear cells from inguinal LN of HIV-infected EC and cervical LN of chronic progressors (CP) from the SCOPE cohort at UCSF and the Center for Investigation of Infectious Diseases (INER-CIENI) in Mexico City, respectively. We index sorted single HIV-specific CD8+ T cells, as identified by MHC-class I tetramers, and subjected these cells for scRNAseq using the SMARTseq-v2 platform. Functional assays were analyzed on a BD LSR II flow cytometer. The results were analyzed using RStudio, FlowJo, and GraphPad Prism. Results: Using an unsupervised scRNAseq analysis approach, we observed distinct clustering between EC cells and CP cells driven by 2264 differentially expressed genes. Compared to CP, EC cells expressed lower levels of cytolytic genes, and heightened expression of several secreted molecules with potential anti-HIV activity, including as CCL5, TNF, and IL32. In order to determine a gene signature that could distinguish EC cells from CP cells, we next used a supervised classification approach, yielding a list of 200 genes that were enriched for immune-related and protein translation-related genes. Within this gene signature, EC cells showed a downregulation of inhibitory receptor genes and an upregulation of specific cytokines and ribosome subunits, implying that these cells are highly functional. We functionally confirmed this signature with ex vivo peptide stimulation polyfunctional cytokine and protein translation assays, finding heightened polyfunctional and protein translation capacity in lymph node CD8+ T cells from HIV EC. Conclusion: Our findings suggest that protective HIV-specific CD8+ T cells in lymphoid tissue of EC are defined by unique non-cytolytic functional features with a high capacity to translate mRNA into protein upon antigen encounter, and call into question known correlates of protection mediated by peripheral blood CD8+ T cells. 135 CHARACTERIZING THE PROVIRAL LANDSCAPE IN HIV-1 ELITE CONTROLLERS Chenyang Jiang 1 , Xiaodong Lian 1 , Joshua Chevalier 1 , Samantha M. Chen 1 , Ce Gao 1 , Xiaoming Sun 1 , Kevin Einkauf 2 , Ben S. Rhee 1 , Kaylee Chang 1 , Jane Blackmer 1 , Bruce D. Walker 1 , Mathias Lichterfeld 2 , Xu G. Yu 1 1 Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA, 2 Brigham and Women’s Hospital, Boston, MA, USA Background: HIV-1 elite controllers (ECs) represent a rare group (less than 1%) of infected individuals with undetectable viral loads in the absence of

Oral Abstracts

133 FTY720 LIMITS T FOLLICULAR HELPER CELL INFECTION IN LYMPHOID SITES OF SIV PERSISTENCE Maria Pino 1 , Sara Paganini 1 , Claire Deleage 2 , Kartika Padhan 3 , Justin L. Harper 1 , Colin T. King 1 , Luca Micci 1 , Barbara Cervasi 1 , Joseph Mudd 3 , Sherrie M. Jean 1 , Kirk A. Easley 4 , Jacob D. Estes 5 , Constantinos Petrovas 3 , Michael M. Lederman 6 , Mirko Paiardini 4 1 Yerkes National Primate Research Center, Atlanta, GA, USA, 2 Leidos Biomedical Research, Inc, Frederick, MD, USA, 3 NIAID, Bethesda, MD, USA, 4 Emory University, Atlanta, GA, USA, 5 Oregon Health and Sciences University, Portland, OR, USA, 6 Case Western Reserve University, Cleveland, OH, USA Background: Lymph nodes (LN) and their resident T follicular helper CD4+ T cells (Tfh) are a critical site for HIV replication and persistence. Therefore, optimizing antiviral activity in lymphoid tissues will be needed to reduce or eliminate the HIV reservoir. In this study, we treated ART-suppressed SIV-infected rhesus macaques (RM) with the lysophospholipid sphingosine-1 phosphate receptor modulator fingolimod (FTY720). With this design, we aimed at exploring the potential utility of fingolimod, approved clinically for multiple sclerosis, in retaining cytolytic lymphocytes in lymphoid sites of SIV persistence, fromwhich they are typically excluded during ART, and to impact on the viral reservoir. Methods: 10 RMs infected with SIVmac239 started TDF/FTC/DTG treatment at day 42 post-infection; ART was continued for 9 months. Group 1 RMs (n=5) received FTY720 at 18 μg/Kg per day and group 2 (n=5) at 500 μg/Kg per day. FTY720 was administered orally once a day during the last 28 days of ART, once viremic control was achieved for all animals. Blood (PB) and lymph node (LN) were collected longitudinally for flow cytometric, histocytometry, RNAscope and DNAscope analyses. Cell-associated SIV-DNA and -RNA were quantified in CD4 T cell subsets, including Tfh, by quantitative PCR (qPCR) and reverse transcription quantitative PCR (RT-qPCR) respectively. Results: FTY720 treatment was safe and well tolerated, and plasma SIV levels remained undetectable (<60 RNA copies/ml) during the entire treatment. FTY720 was remarkably effective, in a dose dependent way, in reducing circulating CD4+ and CD8+ T cells (p<0.01), including those with cytolytic potential (expressing T-bet, perforin, and granzyme-B; p<0.01). FTY720

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CROI 2019