Clinical and Immunometabolic Patterns Determining Efficacy of DCtreatment reinvigorating HIV-1-specific CD8+ T cells in PLWH

Introduction: Heterogeneous dysfunctional states of CD8+ T cells in people living with HIV-1 (PWLH) has limited the efficacy of dendritic cell (DC)-based immunotherapies. Here, we studied associations between improved functional response to Gag-loaded adjuvant-primed DCs of CD8 T cells from PLWH with ART duration, memory subset distribution and exhaustion and metabolic profiles in these cells. Methods: A cohort of n=49 PLWH on ART with undetectable plasma viremia and CD4+ T counts above 400cells/ ml were recruited. Monocyte-derived DC were activated with Poly I:C and 2´3´cdiAM(PS)2 adjuvants in the presence of a pool of HIV-1 Gag peptides and co-cultured with autologous CD8+ T cells. Induction and polyfunctionality of HIV- 1 specific CD8+ T responses was evaluated by IFNγ and CD107a expression by FACS. Functionality of DC- stimulated CD8+ T cells was evaluated by co-culture with autologous CD4+ T cells and the ability to reduce proportions of p24+ CD4+ T cells. Individual or combined anti-PD1, TIGIT, TIM3 antibodies and Metformin were used in some functional assays. Characterization of CD8+ T cell memory subset and exhaustion markers was analyzed by FACS. Metabolic profiles of CD8+ T cells were analyzed by Seahorse. Results: Polyfunctionality and functional capacities to eliminate p24+ CD4+ T cells of HIV-1 specific CD8+ T cell responses from PLWH on ART for more than 10 years (LT-ARTp) significantly improved after activation with adjuvant-engineered DC in vitro (p=0.001 and p=0.0039; respectively). In contrast, CD8+ T cells from PLWH on ART for less than a decade (ST-ARTp) were less responsive to DC (p=0.0024) and unable to increase cytotoxic function (p=0.0156). This was associated with lower frequencies of central memory CD8+ T cells, increased co- expression of PD1 and TIGIT (p=0.0362) and reduced mitochondrial respiration and glycolytic induction after TCR activation (p=0.002). In contrast, enrichment on TIM3+ PD1- cells (p=0.001) and preserved glycolytic induction (p=0.0005) was observed in CD8+ T cells from LT-ARTp. Finally, combined treatment of anti-PD1, anti-TIGIT antibodies and metformin restored cytotoxic properties of dysfunctional CD8+ T cells from ST-ARTp (p=0.0156). Conclusions: We identified new immunometabolic parameters potentially useful to personalize DC-based HIV-1 vaccines and improve specific CD8+ T cell response in different PLWH populations.