摘要目的 探讨基因转移细胞毒性T细胞相关抗原4免疫球蛋白(CTLA4-Ig)和抗T细胞分化群154(CD154)抗体在异种胰岛移植排斥反应中的作用及机理.方法 建立人-大鼠异种胰岛移植模型,用携带CTLA4-Ig基因的重组腺病毒感染移植胰岛细胞,并用抗CD154抗体进行治疗,观察糖尿病大鼠胰岛移植后血糖变化、生存情况及移植物病理形态学改变,检测移植物CTLA4-Ig、胰岛素的表达和移植大鼠白细胞介素2(IL-2)、肿瘤坏死因子(TNF)-α的水平变化.结果 (1)糖尿病大鼠移植后2 d血糖降至正常,对照组血糖平均在移植后8 d升高,抗体治疗组、转染组和联合治疗组血糖分别在18、25和36 d升高.(2)对照组、抗体治疗组、转染组和联合治疗组的移植物存活时间分别为(10.0±2.1)d、(22.0±8.2)d、(28.0±6.5)d和(37.0±9.3)d,各组间比较差异有统计学意义(P＜0.05);移植大鼠生存时间分别为(21.0±5.7)d、(35.0±6.5)d、(48.0±8.5)d和(65.0 ±12.5)d,各组间比较差异有统计学意义(P＜0.05).(3)对照组在移植后1周内,IL-2、TNF-α的水平均急剧上升,较移植前显著升高(P＜0.01).(4)各治疗组移植物见成片的胰岛细胞团,未见淋巴细胞浸润,转染组和联合治疗组移植物可见CTLA4-Ig和胰岛素的表达.结论 基因转移CTLA4-Ig和抗CD154抗体均可抑制异种胰岛移植排斥反应,二者联合效果优于单独使用.

abstractsObjective To study the effects of gene transfer cytotoxic T lymphocyte associated antigen 4 immunoglobulin(CTLA4-Ig)and anti-cluster of differentiation 154(CD154)mAb on the rejection of rat islet xenografts.Methods Human islets were infected with the recombinant adenovimses containing CTLA4-Ig gene.Transduced islets were transplanted under the left kidney capsule of diabetic rats.And then the animal model were treated with anti-CD154 monoclonal antibodv.The changes of blood sugar were measured and the survival rates of grafts and transplantation rats were observed after transplantation.The morphological changes of grafts were observed.Expression of CTLA4-Ig and insulin were detected by immunohistochemical staining and cytokines were quantified by ELISA.Resuits (1)The blood glucose of transplantation rats decreased to normal level on 2th day post-transplantation.The average level blood glucose of control group A,anti-CD154mAb treatment group B,transfected group C and associated treatment group D increased on day 8,18,25,36,post-transplantation respectively.(2)The grafts of group A,B,C and D survived for(10.0±2.1)d,(22.0±8.2)d,(28.0±6.5)d and(37.0±9.3)d respectively.The survival of grafts in group D was significant longer than that in group A,B and C,respectively;The survival of group B and C were significantly prolonged compared with group A and the survival of group B was significantly different with group C(P＜0.05).The survival of transplantation rats were(21.0±5.7)d,(35.0±6.5)d,(48.0±8.5)d and(65.0±12.5)d in group A,B,C and D,respectively.The survival of transplantation rats compared each other among four groups were same as the survival of grafts(P＜0.05).(3)In control animals(group A),serum IL-2 and TNF-α concentration were elevated to a high level within seven days post-transplantation and significantly increased compared with that before transplantation(P＜0.01).(4)Hematoxylin-eosin staining of grafts showed a lot of islets under the kidney capsule of transplantation rats,no inflammatory cell infihrate and immunohistochemical staining of grafts demonstrated expression of insulin protein at islets in group B,C and D.These grafts positively stained for CTLA4-Ig in group C and D.Conclusions Gene transfer CTLA4-Ig and anti-CD154mAb treatment can inhibit the rejection of rat islet xenografts and treatment Ad-CTLA4-Ig and anti-CD154 mAb could induce immune tolerance of islet xenografts.