Bacterially activated B-cells drive T cell differentiation towards Tr1 through PD-1/PD-L1 expression.

•Hfstim- IL-10+ and IL-10− B cells are composed of B10 and T2-MZP, and MZ B cells, respectively.•Hfstim- IL-10+ B cells express CD9, Tim-1, and PD-1, whereas Hfstim- IL-10− B cells express PD-L1 on their surface.•Hfstim- IL-10− B cells produce TGF-β, IL-6, and TNF-α cytokines, and secretes IgM and IgG2b antibodies.•Hfstim-B cell-driven Tr1 cell differentiation is dependent on PD-1/PD-L1 expression.•Hfstim- IL-10− B cells induce Th17 cell differentiation through the secretion of TGF-β.