T cell development in C57BL/6, ABabDII, and ABabDR4 mice. (A) Thymocyte staining. First lane, CD4, CD8 double- and single-positive cells; second lane, CD5 and CD69 staining; third lane, CD3 staining, gated on living lymphocytes; and fourth lane, CD4 and CD8 double- and single-positive cells gated on CD3⁺ cells. One representative FACS plot from each of C57BL/6 (n = 3), ABabDII (n = 6), and ABabDR4 (n = 6) mice. Percentage of the gated cells for the whole population is indicated inside or above the gates. (B) Numbers of CD4 single-positive, CD5⁺CD69⁺, CD4CD8 double-positive, and CD3⁺CD4⁺ thymocytes. (C, left) Representative FACS plots of CD4 and CD8 staining from splenocytes, gated on CD3⁺ living lymphocytes. (C, right) Absolute numbers of CD4 T cells from spleen of C57BL/6, ABabDII, and ABabDR4 mice. The percentage of positive cells is indicated in both A and C. (D) Tcon (left) and Treg (right) cell numbers from spleen. Bars with lighter color indicate the CD44⁺ portion of cells from each subgroup. Summarized data (B, C, and D) from C57BL/6 (n = 3), ABabDII (n = 6), and ABabDR4 (n = 6) mice, shown as means ± SD. **, 0.001 ≤ P < 0.05; *, 0.05 ≤ P < 0.1; n.s., not significant (Mann-Whitney test, two-tailed). In addition, Fig. S2 shows FoxP3 thymic and spleen staining.