HSP90b1 ablation leads to defective compartmentalization but uncompromised function of innate-like B cells. (A-C) Flow cytometric analysis of marginal zone B cells and B1 cells. Representative fluorescence-activated cell sorting (FACS) plots of WT and KO splenic marginal zone B cells (A), peritoneal B1 cells (B), and blood B220⁺CD21⁺CD23⁻ and B220⁺CD5⁺CD11b⁻ cells (C). Numbers on plots are percentages of gated populations. (D) Production of T cell–independent Ab by B cell–specific HSP90b1 KO mice. Anti-TNP IgM was measured before and after immunization with TNP-Ficoll (n = 6 in each group). Error bars represent SD.