Fig. 5.

r1ΔT/r2n mice show altered T helper differentiation and decreased regulatory T cell frequency. (A) Defective differentiation in r1ΔT/r2n CD4⁺ T cells after activation and expansion under Th2 polarizing conditions. Effector CD4⁺ T cells of the indicated genotypes were restimulated with phorbol 12-myristate 13-acetate plus ionomycin, and the percentages of cells secreting the indicated cytokines were enumerated by intracellular staining. Th2 skewing is generally incomplete in this mixed genetic background (129SvEv × C57BL/6), as in C57BL/6 and related inbred strains. (B) Six- to 8-week-old r1ΔT/r2n mice have a significant reduction (P < 0.01) in the percentage of CD4⁺CD25⁺FoxP3⁺ peripheral Treg cells in the spleen (Left) but not the thymus (Right).