The latency reversing agent HODHBt synergizes with IL-15 to enhance cytotoxic function of HIV-specific CD8+ T-cells.

IL-15 is under clinical investigation towards the goal of curing HIV infection, due to its abilities to reverse HIV latency and enhance immune effector function. However, increased potency through combination with other agents may be needed. 3-hydroxy-1,2,3-benzotriazin-4(3H)-one (HODHBt) enhances IL-15-mediated latency reversal and NK function, by increasing STAT5 activation. We hypothesized that HODHBt would also synergize with IL-15, via STAT5, to directly enhance HIV-specific cytotoxic T-cell responses. We show that ex vivo IL-15+HODHBt treatment markedly enhances HIV-specific granzyme B-releasing T-cell responses in PBMCs from ARV-suppressed donors. We also observed upregulation of antigen processing and presentation in CD4+ T-cells, and increased surface MHC-I. In ex vivo PBMCs, IL-15+HODHBt was sufficient to reduce intact proviruses in 1 of 3 ARV-suppressed donors. Our findings reveal the potential for 2nd-generation IL-15 studies incorporating HODHBt-like therapeutics. Iterative studies layering on additional latency reversal or other agents are needed to achieve consistent ex vivo reservoir reductions.