CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

506

Immune Profile During ATI in AELIX-002 HTI Vaccine Trial and Its Role in Post-Intervention Control Cristina Peligero-Cruz 1 , Lucía Bailón 2 , Samandhy Cedeño 1 , Tuixent Escribà 1 , Yovaninna Alarcón-Soto 3 , Analía López 3 , Edwards Pradenas 1 , Anna Pons-Grífols 1 , Anuska Llano 4 , Devi SenGupta 5 , Ian McGowan 6 , Jose Molto 2 , Christian Brander 1 , Beatriz Mothe 1 , for the AELIX-002 Study Team 1 IrsiCaixa Institute for AIDS Research, Badalona, Spain, 2 Hospital Germans Trias i Pujol, Badalona, Spain, 3 Hospital Germans Trias i Pujol, Bandalona, Spain, 4 Institut Universitari Fundació Parc Taulí, Sabadell, Spain, 5 Gilead Sciences, Inc, Foster City, CA, USA, 6 Aelix Therapeutics, Barcelona, Spain Background: Autologous neutralizing antibodies (aNAb) are able to apply selective pressure on rebounding viruses after ART interruption (ATI). Recent findings in CHAMP cohort also show higher frequencies of activated natural killer (NK) cells in post-treatment controllers (PTC). In AELIX-002, a randomized controlled clinical trial testing HTI T-cell vaccines in early-treated PWH, all participants experienced detectable viral rebound during ATI, but lower viremia and longer ART-free periods (>12 weeks) were observed in vaccine recipients in whom vaccination induced robust cytotoxic HTI responses pre-ATI. Here, we explore humoral, innate, and T cell responses during ATI. Methods: We used plasma and PBMC from 41 AELIX-002 participants (1) before ART was initiated (pre-ART), (2) at study entry (BL), (3) at first recrudescence timepoint (ATI-Rc), at peak viremia (ATI-Pk), (5) at viral setpoint (ATI-Setp) and (6) at the end of ATI (ATI-end). Neutralizing antibodies were measured against a panel of 6 HIV-1 pseudoviruses (Tier 1 and 2) and the pre-ART autologous virus in a standard TZM-bl cell-based assay. T, B and NK cell composition, activation and exhaustion were measured by flow cytometry. Total HIV- and HTI-specific responses were measured by IFNg ELISpot. Results: Pre-ART, only three participants showed low-to-moderate neutralization of NL4-3 pseudovirus and, one participant, of the autologous virus. At ATI-Pk, 27% placebo and 4% vaccinees neutralized NL4-3, while 21% placebo and 12% vaccinees had detectable neutralization to the pre-ART autologous virus. Despite viral recrudescence occurring in all participants, vaccinees who remained off ART > 12 weeks had stronger and more HTI-focused responses at ATI-end compared to the rest of participants and presented a unique immunological profile characterized by i) lower levels of plasma B cells, ii) lower levels of activated B and CD8 T cells, and iii) less exhaustion after peak viremia and up to ATI-end. Unlike PTC, no increase in activated NK was seen in vaccinees who remained off ART for >12 weeks at any timepoint. Conclusion: After HTI-vaccination, the immune profile of participants remaining off ART for >12 weeks was different from those described in other studies on post-treatment controllers. While no significant contribution of humoral and innate responses was detected, durable HTI-specific responses and lower B- and T-cell activation profiles were maintained during ATI despite viral recrudescence. IL-1β Blockade in PWH on ART Enhanced Host Antiviral Responses and Cytotoxic Effector Functions Sulggi A. Lee 1 , Ashish A. Sharma 2 , Naseem Sadek 2 , Danny Li 1 , Ashok K. Dwivedi 1 , Rachel L. Rutishauser 1 , Steven G. Deeks 1 , Rafick P. Sekaly 2 , Priscilla Y. Hsue 1 , Jeffrey A Tomalka 2 1 University of California San Francisco, San Francisco, CA, USA, 2 Emory University, Atlanta, GA, USA Background: Plasma IL-6 levels are amongst the strongest predictors of mortality in people with HIV (PWH) on ART, and IL-1β, an upstream regulator of IL-6, may be the major driver of this risk. In vivo IL-1β blockade with the monoclonal antibody, canakinumab, significantly reduced arterial and bone marrow inflammation in our prior pilot study of PWH on ART. Here we now identify the host immune mechanisms associated with IL-1β blockade, using single cell mass cytometry (CyTOF) and transcriptomic approaches. Methods: A total of 10 PWH on ART with known cardiovascular disease (CVD) or 1 traditional CVD risk factor, were administered a single subcutaneous dose of 150 mg canakinumab and followed for 12 weeks. Biospecimens were collected at weeks 0, 4, and 8 weeks post-treatment. We performed bulk RNA sequencing from PBMCs, sorted CD4+ T cells, and CyTOF from PBMCs. We performed differential gene expression analysis with correction for multiple testing using the Benjamini-Hochberg method. Gene set enrichment analyses were performed using the MSigDB database. Results: We observed a significant reduction in plasma IL-1β and IL-6 levels after canakinumab treatment. RNA-seq from bulk PBMCs showed significant induction of interferon signaling and downregulation of genes pathways reflecting CD8+ T cell exhaustion after canakinumab treatment. RNA-seq from

were upregulated on HIV-1 reservoir cells with intact proviruses, consistent with immune selection primarily mediated by innate immune responses. Conclusion: These data suggest accelerated and more efficient immune selection of HIV-1 reservoir cells when ART is started during early disease. Immune selection appears to be predominantly driven by innate immune responses in early infection, while the therapeutic T cell vaccine had no detectable effect. Identification and Targeting of Metabolic Profiles in CTL-Resistant, HIV-Infected CD4+ T-Cells Alberto Herrera , Louise Leyre, Jared Weiler, Paul Zumbo, Doron Betel, R. Brad Jones Weill Cornell Medicine, New York, NY, USA Background: HIV-specific CTL responses remain present even under long term ART, in association with residual HIV expression. Selection of CTL-resistant reservoir-harboring clones may contribute to HIV persistence, with BCL-2 overexpression being a previously reported mechanism. To identify additional mechanisms of resistance, we developed an in vitro model that compares infected cells surviving CTL pressure to non-targeted infected bystander cells in the same environment. Here, we highlight a specific metabolic profile enriched in CTL-resistant infected cells. Methods: CD4+ T-cells were infected with HIVJRSCF (WT) or a variant containing an escape mutation in the Gag-TW10 epitope (TW10esc). Killing assays were performed by labeling infected T-cells with CTFR (WT) or CFSE (TW10esc) dyes, then culturing these together with a TW10-specific CTL clone. Surviving WT infected and bystander TW10esc-infected cells were sorted based on HIV-Env expression and profiled by RNAseq, CITEseq and flow cytometry. Killing assays were also performed with pre-treatment of infected cells with the FDA approved antimalarial Atovaquone (ATQ) and iron chelator Deferoxamine (DFO). Results: WT-infected survivors exhibited distinctive transcriptional and protein expression profiles, relative to bystanders (Figure 1). GSEA analysis of RNAseq data revealed that among several dysregulated pathways, WT-survivors were negatively enriched for Hallmark Glycolysis (n=4, NES = -1.74, Padj = 2.96e-05) and byproducts of active metabolism such as Hallmark Hypoxia (NES = -1.79, Padj = 1e-05). Flow cytometry on WT-survivors showed enrichment of cells expressing lower levels of cellular reactive oxygen species (ROS) (n=4, mean = -24.41% +/- 13.62, P=0.037). Pre-treatment of infected cells with ATQ, to increase ROS accumulation, and DFO, to induce hypoxia, modestly and robustly enhanced susceptibilities of infected cells to elimination by CTL respectively (ATQ: n=5, P = 0.09 ; DFO: n=4, P = 0.015; ATQ+DFO: n=4, P = 0.051). Conclusion: Oxidative disbalance contributes to CTL mediated killing. Our results suggest that lower levels of ROS and hypoxic responses in HIV-infected cells with particular metabolic features renders these cells less susceptible to killing by CTL. Treatment with FDA-approved and well-tolerated ROS inducer ATQ and hypoxia-inducing iron-chelator DFO increased CTL mediated elimination of infected cells in vitro. Targeting metabolic balance may be a strategy to enhance elimination of persistent HIV-infected cells.

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Poster Abstracts

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CROI 2024 133