(A) Flow cytometry analysis of CD21 versus CD23 in gated live, B220+ B cells showing that Ets1−/− and CD19-Cre Ets1fl/fl mice lack CD21hiCD23lo marginal zone B cells. Gate positions were adjusted to enclose the major cell populations. (B) Quantification of the percent of marginal zone B cells and the mean fluorescence intensity (MFI) of CD23 on follicular B cells (n = 8 Ets1+/+, 6 Ets1−/−, 11 CD19-Cre Ets1+/+, and 8 CD19-Cre Ets1fl/fl mice). (C) Flow cytometry analysis of B220 versus CD138 in gated live cells showing that Ets1−/− and CD19-Cre Ets1fl/fl mice have increased percentages of B220loCD138+ Ab-secreting plasma cells. (D) Quantification of the percent of ASCs in the spleen and lymph nodes of the various strains of mice (n = 7 Ets1+/+, 6 Ets1−/−, 9 CD19-Cre Ets1+/+, and 11 CD19-Cre Ets1fl/fl mice). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. ns, not significant.