successfully released the abolished IL-2 production caused by PGE2, and reversed the IL-2 level back to that of no-PGE2 control, while 9h exhibited a relatively highest effect (Fig. ). Taken together, we verified that 9h is a potent HPK1 inhibitor with high molecular activity, which shows promising cellular effects in both target inhibition of Jurkat cells and augment of IL-2 production of hPBMCs.