RNA-Seq of IL-2-KO follicular CD8 T cells and IL-2-KO follicular CD4 T cells

Follicular CXCR5+ PD-1+ CD8 T cells (CD8 Tfc) arise in multiple models of systemic autoimmunity yet their functional contribution to disease remains in debate. Here we define the follicular localization and functional interactions of CD8 Tfc with B cells during autoimmune disease. The absence of functional T regulatory cells in autoimmunity allows for CD8 Tfc development that then expands with lymphoproliferation. CD8 Tfc are identifiable within the lymph nodes and spleen during systemic autoimmunity, but not during tissue-restricted autoimmune disease. Autoimmune CD8 Tfc cells are polyfunctional, producing helper cytokines IL-21, IL-4, and IFN? while maintaining cytolytic proteins CD107a, granzyme B, and TNF. During autoimmune disease, IL-2-KO CD8 T cells infiltrate the B cell follicle and germinal center, including the dark zone, to induce AID in vitro in naïve B cells via IL-4 secretion. CD8 Tfc represent a unique CD8 T cell population with a diverse effector cytokine repertoire that can contribute to pathogenic autoimmune B cell response. Overall design: 4 samples sequenced, 2 biological replicates. Pooled 15-16 day old IL-2-KO CD4+ CXCR5+PD-1hi, Pooled 15-16 day old IL-2-KO CD8+ CXCR5+PD-1hi