Interleukin-10 regulates reservoir establishment and persistence in antiretroviral therapy-treated, SIV-infected macaques

Interleukin (IL)-10 is an immunosuppressive cytokine that signals through STAT3 to regulate T follicular helper cell (TFH) differentiation and germinal center formation, which we propose acts as a determinant of HIV/SIV persistence. In SIV-infected macaques, levels of IL-10 in plasma and lymph node (LN) are induced by infection and not normalized with ART. During chronic infection, plasma IL-10 and transcriptomic signatures of IL-10 signaling were significantly correlated with the cell-associated SIV-DNA content within LN CD4+ memory subsets, including TFH, and predicted the frequency of CD4+ TFH and their cell-associated SIV-DNA content during ART, respectively. Notably, in ART-treated RMs, cells harboring SIV-DNA by DNAscope were preferentially found in the LN B-cell follicle in close proximity to IL-10. Finally, we demonstrate that the in vivo neutralization of soluble IL-10 in ART-treated, SIV-infected macaques significantly reduces B cell follicle maintenance and, by extension, cellular sites of viral persistence, including LN TFH and memory CD4+ T-cells expressing PD-1 and CTLA-4. Thus, these data support a role for IL-10 in maintaining a pool of target cells in lymphoid tissue that serve as a niche for viral persistence. Targeting IL-10 signaling to impair CD4+ T-cell survival and improve antiviral immune responses may represent a novel approach to limit viral persistence in ART-suppressed people living with HIV. Overall design: Evaluation of the safety and bioactivity of IL-10 neutralization in SIV-infected rhesus macaques receiving short-term ART.