Role and mechanism of human Kupffer cells in liver allo-geneic transplantation

Abstract

Objective To explore the possible role and mechanism of the Kupffer cells (KCs) in liver allo-geneic transplantation at the early stage. Methods In vitro cell contact coculture system was established. Culture supernatants were collected respectively on the 1st, 2nd, 4th, 6th d after cocul-ture and the KCs and PBMCs were harvested on the 6th day after culture. The expression of HLA-G on the membrane of the KCs and PBMCs was detected with immunochemistry. Nitrate reduction test was used to determine the concentration of nitric oxide. IFN-γ, IL-10, TGF-β1 cytokine levels in the supernatants were also measured with ELISA. The proliferation of lymphocytes was evaluated with MTT. Results six days later, no HLA-G molecules were detected on the membrane of the KCs and PBMCs. In the experimental group containing KCs, the levels of NO, IL-10 and TGF-β1 was signifi-cantly increased(P<0. 05), while the levels of IFN-γ was relatively lower(P<0. 05) as compared to the experimental group without KCs. No IL-10 and IFN-γ were detected in the control group, and on-ly few NO and TGF-β1 was found in the control group with KCs. MTT test showed that the value of optical density was lower in the experimental group with KCs than that in any other group(P<0. 05).Conclusion No HLA-G is expressed on the membrane of KCs and PBMCs after contact coculture.KCs may participate in regulating production of NO and Th2/Th3-like cytokines and suppressing the proliferation of lymphocytes, through which KCs probably take part in inducing immunotolerance of liver transplantation in early stage. Key words: Liver transplantation; Kupffer cell; Mixed lymphocyte culture; Immunotoler-ance; Nitric oxide; Cytokine