HPK1 enhances JNK activation in primary CD4⁺T lymphocytes.

CD4⁺ T cells from LNs of DO 11.10 TCR tg mice were stimulated with OVA peptide for 24 hours and infected with the indicated retroviruses. After 2 days of expansion, the cells were sorted for infected EGFP-positive cells. One day later the cells were either left untreated (–) or restimulated with plate-bound αCD3ε mAb for 30 minutes (+). Whole cell protein extracts were prepared from 3 × 10⁵ cells each and immunoassayed using the indicated Abs.