Patterns in donor-specific mRNA and protein production of Th1 and Th2 cytokines by graft-infiltrating lymphocytes and PBMC after heart transplantation.

Abstract

We used RT-PCR and ELISA to study the kinetics of IL-2 (Th1) and IL-4 (Th2) both on mRNA and protein level from "naive" PBMC and "primed" graft-infiltrating lymphocytes (GIL) obtained from a heart transplant recipient. For this purpose, these cells were stimulated for 1-48 h with donor and control third-party antigens. Only stimulation of GIL with donor-specific antigen resulted in early detectable IL-2 and IL-4 mRNA and protein levels. Maximal relative IL-2 mRNA levels were significantly higher than maximal relative IL-4 mRNA levels (100-fold) in both GIL and PBMC after donor-specific stimulation. This was accompanied by a maximum protein production of 908 pg/ml IL-2 and 19 pg/ml IL-4 by GIL, and of 82 pg/ml IL-2 and undetectable IL-4 production by PBMC. These results suggest that, after stimulation donor-specific "primed" GIL, and not "naive" PBMC, rapidly produce abundant levels of IL-2 (Th1) and IL-4 (Th2) at both the transcriptional and protein level.