Prostaglandin E2 (PGE2), a known immune-suppressive molecule, is able to restrain T cell activation and IL-2 production. We therefore tested whether 7m and 9h could overcome this repression. It was shown that 5 nM of PGE2 was able to abolish the IL-2 secretion of hPBMCs (Fig. ). Targeting HPK1 by 0.3 μM of 7m, 9h and 6