Rapamycin combined with donor bone marrow-derived immature dendritic cells induces mouse skin allograft tolerance

OBJECTIVE: To investigate the synergic effects of rapamycin and donor bone marrow-derived immature dendritic cells (DCs) in inducing skin allograft tolerance in mice. METHODS: The recipient BALB/c mice receiving transplantation of skin allograft from C57BL/6 mice were divided into control group (without perioperative treatments), rapamycin group (receiving rapamycin at 1 mg.kg(-1).d(-1) by gavage for 7 consecutive 7 days after skin transplantation), immature DC group (receiving an injection of donor bone marrow-derived immature DCs of 2 x 10(6) via tail vein before skin transplantation), combined group (receiving an injection of the DCs of 2 x 10(6) before transplantation and rapamycin at 1 mg.kg(-1).d(-1) for 7 consecutive days after transplantation). The survival time of the skin allograft was observed in each group. RESULTS: The survival time of the skin allograft in the control, rapamycin, immature DC and immature DC +rapamycin groups were 6.9-/+1.9, 12.3-/+3.0, 17.0-/+3.4 and 20.8-/+3.6 days, respectively, showing significant differences among the groups (P<0.05), and SNK test also indicated significant differences between every two groups. CONCLUSIONS: Rapamycin and donor bone marrow-derived immature DCs have synergic effects in inducing skin allograft tolerance in mice.