Bcl6^+/−Bach2^+/−splenic B cells undergo rapid differentiation ex vivo. (A) Flow cytometry was performed on mouse splenic B220⁺ cells treated with LPS for 48 hours. Numbers in outlined areas indicate percent CD138⁺ (plasma) cells. (B) qRT-PCR analysis of Prdm1, Xbp1, and CD138 mRNA levels in LPS-treated splenic B cells. Data are presented as mean ± standard error of the mean from 2 independent experiments (A-B). *P < .01 when compared with single heterozygous or WT mice; 2-tailed Student t test.