Inhibition of allogeneic T-cell responses by Kupffer cells expressing indoleamine 2,3-dioxygenase in vitro / 中华肝胆外科杂志

ABSTRACT

Objective To investigate kupffer cells (KCs) expressing indoleamine 2,3-dioxygenase(IDO)in the inhibition of allogeneic T-cell proliferation in vitro. Methods Real-time PCR was used to investigate the expression of IDO mRNA and FasL mRNA in KCs pretreated with or without IFNγ. High performance liquid chromatography was used to analyze the catabolism of tryptophan by IDO from KCs. Allogeneic T-cell response was used to confirm the inhibition of KCs in vitro. The proliferation of lymphocytes was detected using [3 H] thymidine incorporation. Cell cycle and lymphocyte apoptosis were evaluated by flow cytometric assay. Results Real-time PCR revealed IDO mRNA and FasL mRNA expression in KCs pretreated with IFN-γ. IDO catabolic effect was confirmed by a decrease in tryptophan and increase in kynurenine concentration. KCs expressing IDO and FasL from BABL/c mice acquire the ability to suppress the proliferation of T-cells from C57BL/6, which could be blocked by the addition of 1-methyl-tryptophan and anti-FasL antibody. The co-cultured T-cells with KCs expressing IDO and FasL could induce allogeneic T-cell apoptosis and exhibited cell-cycle arrest in G1. Conclusion In addition to the Fas/FasL pathway, IDO may also play an important role in KCs to inhibit allogeneic T-cell proliferation in vitro.