Flow cytometry analysis of αβ T cells in CD4+ T-cell-deficient mice. Spleen cells from C57BL/6 mice or CD4+ T-cell-deficient mice were stained with anti-TCRβ, anti-CD8, and anti-CD4 MAbs (H57-FITC, 53-6.7-PerCP, and GK1.5-PE, respectively, from PharMingen and Beckton-Dickinson). Plots show TCRβ-gated cells. Samples were from (a) a 16-week-old C57BL/6 mouse, (b) a 6-month-old CD4+ T-cell-deficient mouse, and (c) a 6-week-old CD4+ T-cell-deficient mouse.