联合阻断CD28/B7和ICOS对同种异体C57BL/6小鼠皮肤移植的影响

The effect of costimulatory blockade with anti-inducible costimulator antibody combined with CTLA4Ig on prevention of skin allograft rejection

目的探讨CD28/B7共刺激通路阻断剂和ICOS/ICOSL共刺激通路阻断剂对同种异体小鼠皮肤移植的影响。方法实验动物随机分为4组,每组6只,供体、受体均为C57BL/6。CTLA4Ig处理组;ICOSIg处理组;CTLA4Ig+ICOSIg处理组;空白对照组。将C57BL/6小鼠背部全层皮肤移植于同种小鼠中段背部。前3组分别以150mg/kg的抗体经腹腔注射,空白对照组只注射同等量的生理盐水,注射时间为皮肤移植后0、2、4d,术后观察皮肤存活情况。术后6d分别处死各组受体鼠和供体鼠,取受体脾脏淋巴细胞与供体脾脏淋巴细胞作混合淋巴细胞反应(MLR),用MTT法测定细胞活力和细胞增殖反应。术后7d切取皮肤移植物作组织学分析。结果与对照组相比,各阻断剂单独治疗组能明显延长移植物的存活时间(<0.05),各阻断剂治疗组淋巴细胞对供体淋巴细胞产生特异性低反应(<0.05),能有效抑制淋巴细胞对同种抗原的免疫应答。组织学检查发现,各抗体治疗组移植皮肤结构基本正常。结论 CTLA4Ig、ICOSIg可以抑制免疫应答,诱导移植皮肤发生免疫耐受,延长存活时间。

Objective To study the effects of costimulatory blockade with ICOS-Ig combined with CTLA4Ig on prevention of skin allograft rejection.Methods Allogenetic full-thickness skin graft was performed in the middle of the back and transplanted into 24 C57BL/6 mice whose were divided averagely into four groups in random：CTLA4-Ig treatment group,ICOS Ig treatment group,CTLA4Ig＋ICOSIg treatment group and Control group.The corresponding antibodies were injected intraabdominally with a dose of 150mg/kg at day 0,2,4 after skin graft in CTLA4-Ig,ICOS Ig and CTLA4Ig＋ICOSIg groups,but just injected the same amount of normal saline.The survival graft was observed after transplantation.Recipient mice and donor mice were killed at day 6.Mixed lymphocyte responses（MLR）of the spleen cells were performed respectively,the activity and proliferation ability of the cells were determined by MTT method,histology of the skin graft was observed HE staining.Results The survival time was obviously prolonged（P〈0.05）with low immunoreaction to donor lymphocyte（P〈0.05）in CTLA4-Ig and ICOSIg and CTLA4Ig＋ICOSIg groups than in normal controls.Histological examination found that the transplanted skins were essentially normal in antibody treatment groups.Conclusions CTLA4Ig and ICOSIg can restrain the immune response of skin transplantation,induce immunotolerance and prolong the survival time of the graft.