Influence Of PD-L1Ig Combined With Rapamycin On The Survival Of Pancreas Allografts In Rats

Objective To study the influence of costimulatory blockade PD-L1Ig combined with rapamycin on the survival of pancreas allografts in rats.Methods F344→Lewis rat pancreas transplantation was performed. Experimental animals were divided into four groups in random,10 rats for each.groupA(control),groupB(PD-L1Ig),groupC(RPM)and groupD(PD-L1Ig+RPM).The survival of pancreas allografts,serum glucose of the recipients and the pathological changes of the allografts were observed.At dayl,day4,day7 and day10 after transplantation,the level of interleukin(IL)-2,interferon-γ(IFN-γ)in the grafts was determined by RT-PCR;Also,the mixed lymphocyte reaction(MLR) of the donor with the recipient spleen cells were performed.Results Significantly prolonged allografts survival time was seen in group B,C and D compared with control,with the longest in group D. The lowest serum glucose and fewest lymphocytes infiltrating grafts were also seen in group D.Down-regulation of IL-2 was observed in the Group B,C and D,and the levels in Group D were lowest.Down-regulation of IFN-γwas observed in the Group B,C and D,but there was no significantly difference between Group D and B or Group D and C.The donor specific MLR was suppressed in spleen cell cultures.Conclusion Combined use of PD-L1Ig and rapamycin(RPM) may suppress the cell-mediated immune responses and pancreas allograft rejection effectively and promote further prolongation of the survival of pancreas allografts.