Normal up-regulation of FasL mRNA and surface expression in WASp-deficient T cells. (A) Induction of FasL mRNA measured by real-time quantitative polymerase chain reaction (RT-qPCR) after exposure of activated CD4⁺ T lymphocytes to 1 μg/mL plate-bound anti-CD3 antibody for 6 hours. Induction of mRNA is shown relative to stimulation with isotype control antibodies. Average and SD of mRNA induction is shown. Similar results were observed in 2 independent experiments. (B) WT and WASp-deficient T cells were restimulated with anti-CD3 for the indicated number of hours, and surface FasL was quantitated by FACS. The mean change in geometric mean fluorescence is shown for WT and WASp-KO T cells restimulated for the indicated periods of time with anti-CD3. The data are the average ± SEM of 3 independent experiments.