Expression of the c-kit proto-oncogene in rat hepatic allografts during acute rejection

The role of the c-kit proto-oncogene in organ allograft rejection is not kn own. We investigated the level of c-kit expression following allogeneic tra nsplantation of ACI rat liver grafts into LEW recipients. We studied c-kit mRNA and protein expression in groups of transplant recipients receiving he patic isografts, hepatic allografts, or hepatic allografts after donor-spec ific blood transfusion (DST). Pretransplantation DST significantly prolonge d survival of hepatic allografts. Infiltrates expressing c-kit were observe d in allografts to untreated rats but not in groups receiving isografts or allografts following DST. Northern analysis also demonstrated abundant c-ki t mRNA transcripts in the untreated allograft group in contrast to the isog raft and the DST-treated groups. In addition, significantly more transcript s for interleukin-12 (IL-12), which is synergistic with c-kit, were present in untreated than in DST-treated allograft groups. In contrast, transformi ng growth factor beta (TGF-beta), which inhibits c-kit synthesis, was expre ssed abundantly in hepatic allografts to DST-treated rats but not in allogr afts to untreated animals. Transcripts for IL-10, which inhibits IL-12 prod uction, were significantly more plentiful in hepatic allografts following D ST than in those without DST. The results suggest that c-kit proto-oncogene expression in infiltrating cells is associated with rat hepatic allograft rejection.