HPK1 enhances FasL expression on primary CD4⁺ T cells.

CD4⁺ T cells from LNs of DO 11.10 TCR tg mice were stimulated with OVA peptide and infected. After 3 days of expansion, the cells were either left untreated or restimulated with plate-bound αCD3ε mAb for 3 hours, stained with biotin-conjugated αFasL mAb, washed, incubated with PE-conjugated streptavidin, and analyzed by FACS. Mean values from 3 independent experiments are shown.