Objective: To investigate the effect of CD8(+)CD28(-) suppressor T cells(Ts) induced by dendritic cell(DC) with major histocompatibility complex 1(MHC-1) expression RNA interference on immune tolerance in rat intestinal transplantation.
Methods: The expression level of CD8(+)CD28(-)Ts were successfully induced by DC with MHC-1 expression interfered by RNA interference technique under the stimulator of allograft antigen. Orthotopic intestinal transplantation was performed in 36 rats by modified three cuffs method. The recipients were randomly divided into three groups(12 rats in each group):group A was experimental group with CD8(+)CD28(-) Ts being administrated, mixed T cells were injected in group B, while in group C, NS were administrated. On the first day and the seventh day posttransplant, the 36 rats of the 3 groups were administrated through vena dorsalis penis respectively. Six rats were selected randomly from each group and the animals were sacrificed on the 14 th day postoperatively, serum levels of TGF-beta, IFN-gamma and the values of Na(+)-K(+)-ATPase activity of the intestinal graft were assayed and the intestinal pathologic morphology, intestinal allograft survival were observed concerning the remainders.
Results: On the 14 th day after operation, the expression levels of TGF-beta and IFN-gamma in group A were significantly up-regulated as compared with those in group B and group C(P<0.05). Na(+)-K(+)-ATPase activity in group A was(6.3+/-1.0) kU/g, much higher than the levels of group B(3.6+/-0.9)kU/g and group C(2.9+/-1.3) kU/g and the differences were significant(P<0.05). The data suggested preliminarily that pathological scores of intestinal graft in group A were lower than those in group B and group C. The survival time of the recipients in group A was 32.0 days, much longer than that in group B (17.5 days, P<0.05) and group C(21.0 days, P<0.05).
Conclusion: CD8(+)CD28(-) Ts induced by DC with MHC-1 expression RNA interference can alleviate acute rejection and lead to immune tolerance in rat intestinal transplantation.