Restriction of innate Tgd17 cell plasticity by an AP-1 regulatory axis [multiome]

IL-17-producing gd T (Tgd17) cells are innate-like mediators of intestinal barrier immunity. While Th17 cell and ILC3 plasticity have been extensively studied, the mechanisms governing Tgd17 cell effector flexibility remain undefined. Here, we combined type 3 fate-mapping with single cell ATAC/RNA-seq multiome profiling to define the cellular features and regulatory networks underlying Tgd17 cell plasticity. During homeostasis, Tgd17 cell effector identity was stable across tissues, including for intestinal T-bet+ Tgd17 cells that restrained IFNg production. However, S. typhimurium infection induced intestinal Vg6+ Tgd17 cell conversion into type 1 effectors, with loss of IL-17A production and partial RORgt downregulation. Multiome analysis revealed a trajectory along Vg6+ Tgd17 effector conversion, with TIM-3 marking ex-Tgd17 cells with enhanced type 1 functionality. Lastly, we characterized and validated a critical AP-1 regulatory axis centered around JunB and Fosl2 that controls Vg6+ Tgd17 cell plasticity by stabilizing type 3 identity and restricting type 1 effector conversion.