Defects in immune cells with spontaneous germinal center formation in ABIN1[D485N] mice. (A–F and H) Flow cytometric profiles of spleen (SPL) and LNs. Profiles were gated on: lymphocytes by FSC/SSC (C–F and H); live cells (A); TCR-β⁺ CD4⁺ (D and E), and B220⁺ (C and F). The numbers within figures indicate the percentages of different cells. GC B, germinal center B cell. (A) Flow cytometric dot plots of spleen (top) and LN (bottom) showing frequencies of the CD11b⁺ GR-1⁺ (macrophages and granulocytes) population in ABIN1[D485N] and WT mice. (B) Total cell numbers in spleens of ABIN1[D485N] mice compared with WT. Error bars show the mean ± SEM. ***, P < 0.001 (two-tailed Students t test). (C) Expression of B cell activation markers from WT (shaded area) and ABIN1[D485N] (black line). (D–F) Contour plots (left) and graphical analysis (right) showing percentages of cell populations in spleen (top) and LN (bottom). Each symbol represents one mouse and the horizontal bars show the mean of the values obtained. (D) Activated (CD4⁺ CD44^hi CD62L^lo) and naive (CD4⁺ CD62L^hi) T cells. (E) T_fh cells (CD4⁺ CXCR5⁺ PD-1 ^hi). (F) Germinal center B cells (B220⁺ GL-7⁺ CD95⁺). (G) Immunohistochemistry of spleens from 16-wk-old mice with germinal centers (brown) stained with peanut agglutinin (PNA). Bars, 0.5 mm. (H) Expression of CD138 and B220 in spleen showing plasma cells in ABIN1[D485N] mice and WT mice. All mice analyzed were 12–16 wk old, and data are representative of at least three independent experiments with three to four mice of each genotype (A-F and H) or single experiment with six mice per genotype (G).