Experimental Study On The Induction Of Immune Tolerance Of CTLA4-Ig Gene Transfection In ROLT

Objective: This study was conducted to build experimental model of ROLT with the character of acute rejection; and, to study the effect of CTLA4-Ig on preventing in ROLT.Methods: Twenty ROLT models were established by Kamada two-cuff technique, with inbred female DA rats and female LEW rats served as donor and recipient respectively. Using ex vivo gene transfer technique, CTLA4-Ig gene was introduced to the liver graft during cold preservation and express locally in the graft. The recipients were randomly divided into 2 groups: rejection group A (DA→LEW, n=10) ,CTLA4-Ig treatment group B (DA→LEW, n=10) . Serum sample taken from each recipients were evaluated the changes of serum biochemistry. Every 2 recipients from each group sacrificed at 7 d post-transplantation were evaluated the graft histology. The other 8 recipients were left in each group to observe the animal survival time.Results: Rat orthotopic liver transplantation was performed in the strong rejecter combination of DA to LEW .This allogenic model was stable and survival time without immunosuppression agents was less than 14 days. DA and LEW rat strain combination can be applied to construct rejection and tolerance model of rat liver transplantation. The mean IL-2 concentration in serum is 362.31±49.26 ng/L on day 1 pretransplant. In A group, serum IL-2 concentration was elevated to a high level within 7 days post-transplantation. In contrast, in B group, IL-2 concentration in serum was maintained at a relative low level. The serum concentrations of ALT,AST,TBIL in group A were higher than in group B at 7day post-transplantation (P<0.05) .Histological examination of allografts in group B demonstrated a mild to moderate periportal inflammation and mild injury to liver graft on day 7 post-transplantation. Conclusion: Using ex vivo gene transfer technique, CTLA4-Ig gene was introduced to the liver graft during cold preservation. CTLA4-Ig gene transfecting liver prolonged the survival of liver allograft. Application of CTLA4-Ig can prevent reject and induce to immune tolerance in DA→LEW ROLT model.