Normal B cell development in nonimmunized SFR KO mice. (A) Total splenocyte counts, as well as numbers and proportions of T cells and B cells, were determined in WT (n = 14) and SFR KO (n = 14) mice (8–10 wk old). Results are pooled from four independent experiments. (B) Same as A, except that Tfh cells, GC Tfh cells, and GC B cells were enumerated (WT, n = 3; SFR KO, n = 3 for Tfh cells and n = 4 for GC B cells; 14–20 wk old). (C) Same as A, except that MZ, transitional 1 (T1), transitional 2 (T2), and follicular (FO) B cells were analyzed (WT, n = 3; SFR KO, n = 3). (D) B cell development was analyzed in bone marrow of WT and SFR KO mice (8–10 wk old). The indicated B cell populations, in addition to B220⁻ B cells, were enumerated (WT, n = 4; SFR KO, n = 4). im, immature; m, mature. (E) B-1a and B-1b B cells were enumerated in the peritoneal cavity of WT and SFR KO mice (16–20 wk old; WT, n = 3; SFR KO: n = 3). (F) T reg cells were enumerated in spleen of WT and SFR KO mice (16–20 wk old; WT, n = 3; SFR KO, n = 3). Results are from one experiment (B–F). Each symbol represents a mouse. *, P < 0.05 (two-tailed Student’s t test). Data are presented as mean ± SEM. For all panels of all figures, representative dot plots, contour plots, or histograms are shown on the left, whereas data for multiple independent mice are depicted on the right. Specific populations are boxed or highlighted by horizontal lines. Percentages are shown in the boxes or above the lines. ns, not significant; SPC, spleen cells.