KINETICS OF IL-2 AND IL-4 MESSENGER-RNA AND PROTEIN-PRODUCTION BY GRAFT-INFILTRATING LYMPHOCYTES RESPONSIBLE FOR REJECTION AFTER CLINICAL HEART-TRANSPLANTATION

During cardiac rejection we studied the kinetics of IL-2 and IL-4 mRNA and subsequent protein production by in vivo primed graft-infiltratin g lymphocytes (GIL), using semiquantitative RT-PCR and ELISA Following in vitro stimulation with either donor or third-party antigens, mRNA expression of IL-2 and IL-4 were already detectable 1-2 h after stimul ation, while their protein production could be measured from 4 h onwar ds at least until 48 h. At both the mRNA and protein level, we measure d a donor-specific signal for IL-2 and for IL-4 production (p = 0.02), white the relative donor-specific IL-2 mRNA level was significantly h igher than the relative IL-4 mRNA lever (p = 0.002). These observation s suggest that after in vitro challenge with donor antigens, GIL obtai ned from rejecting cardiac allografts predominantly produce IL-2 mRNA and protein.