Influence of Interferon-gamma Deficiency in Immune Tolerance Induced by Male Islet Transplantation

ABSTRACT

BACKGROUND: Traditionally, interferon-gamma (IFN-gamma) was regarded as a pro-inflammatory cytokine, however, recent reports suggested role of IFN-gamma in immune tolerance. In our previous report, we could induce tolerance to male antigen (HY) just by male islet transplantation in wild type C57BL/6 mice without any immunological intervention. We tried to investigate the influence of IFN-gamma deficiency on tolerance induction by male islet transplantation. METHODS: To examine the immunogenicity of male tissue in the absence of IFN-gamma, we transplanted male IFN-gamma knock-out (KO) skin to female IFN-gamma KO mice. Next, we analyzed male IFN-gamma KO islet to streptozotocin-induced diabetic female IFN-gamma KO mice. And, we checked the functionality of grafted islet by graft removal and insulin staining. RESULTS: As our previous results in wild type C57BL/6 mice, female IFN-gamma KO mice rejected male IFN-gamma KO skin within 29 days, and did not reject male IFN-gamma KO islet. The maintenance of normal blood glucose level was dependent on the presence of grafted male islet. And the male islet recipient did not reject 2nd challenge of male islet graft also. CONCLUSION: Deficiency of IFN-gamma does not have influence on the result of male skin graft and male islet transplantation. Conclusively, male islet transplantation induced T cell tolerance is not dependent on the presence of IFN-gamma.