Effects of combined genes of CTLA4Ig and IDO in post-liver transplantation immune tolerance of rats

Abstract

Background and rationale for the study. Previous studies showed that CTLA4Ig and indoleamine 2,3-dioxygenase (IDO) genes played regulatory role in organ transplantation but failed to reach satisfactory effects. In this study, we constructed an adeno-virus-mediated gene expressing CTLA4Ig-IDO and established rat liver transplantation models. Recipients were randomly divided into four groups of 10 rats each. During the operation, CTLA4Ig, IDO, and CTLA4Ig-IDO genes, as well as a blank plasmid, were infused into different rat groups via portal vein to determine their effects on inducing immune tolerance. Survival rate of recipients, histological changes of graft liver, post-transplantation liver function, and cytokine levels were observed at day 14 after operation.Results. Serum levels of alanine aminotransferase (ALT), aspartate transaminase (AST), and total bilirubin level (TBIL) in the CTLA4Ig-IDO group were lower than those in the other three groups at 14 days post-transplantation (P < 0.05); mRNA and protein expressions of IL-2 and IFN-γ were higher in the control group, but lower in the CTLA4Ig-IDO group (P < 0.05). By contrast, expressions of IL-4, TGF-b, IL-10, and T lymphocyte apoptosis were higher in the CTLA4Ig-IDO group than those in the other three groups (P < 0.05). The CTLA4Ig-IDO group exhibited mild acute rejection and higher survival rate compared with the other groups (P < 0.05).Conclusion. Compared with using CTLA4Ig or IDO alone, combined transfection of CTLA4Ig-IDO was more effective in inducing immune tolerance after liver transplantation.