IL-10 producing CD8+ CD122+ PD-1+ regulatory T cells are expanded by dendritic cells silenced for Allograft Inflammatory Factor-1

DM Elizondo, TE Andargie, NL Haddock… - Journal of leukocyte …, 2019 - academic.oup.com
Journal of leukocyte biology, 2019academic.oup.com
Abstract Allograft Inflammatory Factor-1 (AIF1) is a cytoplasmic scaffold protein that contains
Ca2+ binding EF-hand and PDZ interaction domains important for mediating intracellular
signaling complexes in immune cells. The protein plays a dominant role in both macrophage-
and dendritic cell (DC)-mediated inflammatory responses. This study now reports that AIF1
expression in DC is important in directing CD8+ T cell effector responses. Silencing AIF1
expression in murine CD11c+ DC suppressed antigen-specific CD8+ T cell activation …
Abstract
Allograft Inflammatory Factor-1 (AIF1) is a cytoplasmic scaffold protein that contains Ca2+ binding EF-hand and PDZ interaction domains important for mediating intracellular signaling complexes in immune cells. The protein plays a dominant role in both macrophage- and dendritic cell (DC)-mediated inflammatory responses. This study now reports that AIF1 expression in DC is important in directing CD8+ T cell effector responses. Silencing AIF1 expression in murine CD11c+ DC suppressed antigen-specific CD8+ T cell activation, marked by reduced CXCR3, IFNγ and Granzyme B expression, and restrained proliferation. These primed CD8+ T cells had impaired cytotoxic killing of target cells in vitro. In turn, studies identified that AIF1 silencing in DC robustly expanded IL-10 producing CD8+ CD122+ PD-1+ regulatory T cells that suppressed neighboring immune effector responses through both IL-10 and PD-1-dependent mechanisms. In vivo studies recapitulated bystander suppression of antigen-responsive CD4+ T cells by the CD8+ Tregs expanded from the AIF1 silenced DC. These studies further demonstrate that AIF1 expression in DC serves as a potent governor of cognate T cell responses and present a novel target for engineering tolerogenic DC-based immunotherapies.
Adaptive immune responses are impaired in CD8+ T cells primed by DC silenced for AIF1.
Oxford University Press