Somatic mutation and class-switch recombination in GC-Bmem and Act-Bmem cells. (A and B) Representative flow cytometry profiles (A) and summary of three independent experiments (B) showing the percentage of IgD⁻IgM⁻ among the GC-Bmem and Act-Bmem cells analyzed at the same time points as Fig. 2 A from the lymph nodes (Each dot represents one mouse, three independent experiments, n = 10–11.) ****, P ≤ 0.0001 by two-way ANOVA. (C and D) As in A and B in the Peyer’s patches (PP). (Each dot represents one mouse, three independent experiments, n = 8.) ****, P ≤ 0.0001 by t test. (E) Graph shows number of somatic mutations (nucleotides, IgH + IgL [H+L nt]) in the antibodies obtained from IgG⁺ GC-Bmem cells IgM⁺ GC-Bmem cells, and Act-Bmem cells, purified after immunization, tamoxifen gavage, and doxycycline administration, as in Fig. 2 A. The data represent three independent experiments with a combined total of 7–15 mice per group. (Each dot represents one antibody, n = 89–168 antibody genes sequenced in each group.) **, P ≤ 0.01; ***, P ≤ 0.001; ****, P ≤ 0.0001 by two-way ANOVA. D, day.