Immune tolerance induced by RelB short-hairpin RNA interference dendritic cells in liver transplantation

BackgroundThe induction of specific immune tolerance for alloantigen is the best method for solving transplant rejection. We have previously reported T-cell tolerance induced by RNA interference (RNAi) RelB dendritic cells (DCs), supporting the possibility of immunologic tolerance in liver transplantation.MethodsA stable model of acute rejection was established in Lewis (RT11) rats that had received a liver graft from dark agouti-RT1a rats. To evaluate the immune tolerance of DCs of different maturity, the rats were randomly assigned to four groups (12 donor/recipient pairs): (1) control-DC group, recipient rats without preinjection; (2) RelB short hairpin (sh)RNAi-DC group, recipient rats with preinjection of tolerogenic DCs by way of RelB silencing; (3) imDC group, recipient rats with preinjection of immature DCs; and (4) lipopolysaccharide-DC group, recipient rats with preinjection of mature DCs. The immune tolerance of the grafts was evaluated by liver function tests (aspartate transaminase, total bilirubin), cytokines (interleukin [IL]-2, IL-4, IL-10 and interferon-γ), and histopathologic examination during the 2 wk after transplantation. The survival time of the rats was also observed.ResultsCompared with the other three groups, the graft survival time was significantly prolonged in the RelB shRNAi-DC group. In addition, RelB shRNAi-DCs resulted in the reduced secretion of IL-2 and interferon-γ and increased levels of IL-10 and IL-4. The symptoms of rejection were obviously alleviated in the RelB shRNAi-DC group, and the rejection activity index was still reduced after 2 wk.ConclusionsInjection of RelB-silenced DCs contributed to the reduced incidence of graft rejection and prolonged the graft survival time. The potential mechanisms involved the regulation and induction of immune-incompetent T cell by DCs.