Inhibition Of Allogeneic T-cell Responses By Kupffer Cells Expressing Indoleamine 2, 3-dioxygenase In Vitro And Vivo

Objective: In this study we investigated kupffer cells(KC) expressing indoleamine 2,3-dioxygenase (EDO) in the inhibition of allogeneic T-cell proliferation after antigen-specific interaction in vitro and vivo. Methods: Real-time PCR investigated the expression of IDOmRNA and FasLmRNA in KCs treated with EFN- γ or not. High performance liquid chromatography (HPLC) analyzed the catabolism of tryptophan by EDO from KCs. Allogeneic T-cell response was used to confirm the inhibition of KC in vitro. The proliferation of lymphocytes was detected using ~3[H] thymidine (~3HTdR) incoporation. Cell cycle and lymphocytes apoptosis were evaluated by flow cytometric assay. BABL/c skin was transplanted to C57BL/6.Donor KCs were injected i.v. at days 14,7,2 before transplantation. Hematoxylin (HE) and in situ terminal deoxynucleotidyltransferase catalyzed dUTP-digoxigenin nick-end labeling (TUNEL-AP) were used to identify infiltrating cells and apoptotic cells in section of skin allografts from 7 days posttransplantation respectively. The survival rate of recipients among groups were analysed by Log-rank test.Results: Real-time PCR revealed an apparent increase expression of IDO and FasL mRNA in the first 6 hs in KC pretreated with IFN- γ , Catabolic...