B cells shape naive CD8 T cell programming and fate decisions

Abstract Renewed interest in the relationship between B cells and CD8 T has revealed direct interactions these cells, despite long-prevailing views that they function independently from one another. In fact, an IL-21-producing “helper” cell subset been described; yet, whether have reciprocal capacity to support is less well-studied. Here, we find influence phenotype of naive, effector, memory cells. MD4 mice, which a fixed BCR repertoire, naive exhibit activated/effector phenotype, including relatively high pAkt, p70-s6K, 4e-bp1, low Foxo1 Eomes. Primary responses subunit vaccination or cell-deficient mice are numerically reduced effector-skewed. Importantly, magnitude 3 months after impaired leading increased susceptibility bacterial challenge. Adoptive transfer WT into results similar effector-skewing upon vaccination, demonstrating phenotypic changes result cell-extrinsic factors. Furthermore, CAR cell-mediated depletion 6-week-old also recapitulated reductions primary numbers their vaccination. agreement with prior literature, peak Listeria m. infection equivalent yet here observe CD127+ phenotype. Together, data indicate perform important, broad role establishment pool subsequent regulation programming following infection.