(A, B) Absolute number of total B cells and frequency of GC B cells in the mesenteric lymph nodes (A) and Peyer’s patches (B) of mice for each indicated genotypes. (C) Growth curve of LPS+IL-4 (LI)-activated splenic B cell culture. (D) Representative CTV dilution plots of activated B cells at 72-hr post-stimulation. (E) Frequency of IgG1, IgG3, and IgA class-switched cells after 72 and 96 hr of stimulation in LI, LPS, and LTD cultures, respectively. (F) Cell cycle profile of LI-stimulated B cells after 48, 72, and 96 hr of culture represented by the frequency of live B cells in G0/G1, S, and G2/M phases. (G) Frequency of dead B cells at 48-, 72-, and 96-hr post LI-activation. (H) Fraction of live B cells undergoing apoptosis as defined by positive staining for anti-cleaved caspase-3 antibody after 48, 72, and 96 hr of LI culture. (I) Cell cycle phase-specific assessment of apoptosis. Frequency of cleaved caspase-3+ B cells in G0/G1, S, and G2/M phases at 48, 72, and 96 hr post-stimulation in LI culture. Data in (A–I) are from two independent experiments with 5–10 mice per genotype. Bars represent arithmetic mean and error bars denote 95% confidence intervals of the measured values. P values were computed using one-way ANOVA analysis (A, B) and two-way ANOVA analysis (E–I) with Dunnett’s multiple comparison test wherein the mean of the DKO Trp53-KO group was compared to the others.