Liver Transplantation Center, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510630, China.
Chin Med J (Engl). 2010 Nov;123(21):3106-9.
Costimulatory signals play a vital role in T cell activation. Blockade of costimulatory pathway by CTLA4Ig or CD40LIg have enhanced graft survival in experimental transplantation models yet mechanisms remain undetermined. We investigated the effects of CTLA4Ig and CD40LIg gene transfer on islet xenografts rejection in rats.
Human islets were infected with recombinant adenoviruses containing CTLA4Ig and CD40LIg genes and implanted beneath the kidney capsule of diabetic rats. Levels of blood sugar, morphological changes, and survival of grafts were recorded. Expressions of CTLA4Ig, CD40LIg and insulin were detected by immunohistochemical staining and cytokines levels were quantified by enzyme-linked immunosorbent assay (ELISA).
Blood glucose levels in transplant rats decreased to normal level on the 2nd day post transplantation. The mean blood glucose in the control group, CTLA4Ig transfected group, CD40LIg transfected group and CTLA4Ig + CD40LIg cotransfected group increased on days 8, 24, 21, 68, post transplantation respectively. The grafts in control group, CTLA4Ig transfected group, CD40LIg transfected group and CTLA4Ig + CD40LIg cotransfected group survived for (8 ± 1), (29 ± 4), (27 ± 3), and (74 ± 10) days, respectively. Survival in CTLA4Ig + CD40LIg cotransfected group was significantly longer. Survivals of CTLA4Ig transfected group and CD40LIg transfected group were significantly longer than control group. In control animals, serum interleukin-2 and tumor necrosis factor α concentration significantly increased within seven days post transplantation. Haematoxylin eosin staining of grafts showed live islets in situ of transplant rats without inflammatory cell infiltration. Immunohistochemical staining confirmed the expression of insulin at islets in all experimental groups.
Transfer of CTLA4Ig and CD40LIg genes, especially the cotransfer of both, inhibits rejection of murine islet xenografts. Downregulated expressions of Th1 cells related cytokines might be related to the beneficial effects.
共刺激信号在 T 细胞激活中起着至关重要的作用。CTLA4Ig 或 CD40LIg 阻断共刺激途径可增强实验性移植模型中的移植物存活，但机制尚不清楚。我们研究了 CTLA4Ig 和 CD40LIg 基因转移对大鼠胰岛异种移植物排斥的影响。
用人重组腺病毒感染胰岛，使其包含 CTLA4Ig 和 CD40LIg 基因，并植入糖尿病大鼠肾包膜下。记录血糖水平、形态变化和移植物的存活情况。通过免疫组织化学染色检测 CTLA4Ig、CD40LIg 和胰岛素的表达，并通过酶联免疫吸附试验（ELISA）定量细胞因子水平。
移植后第 2 天，移植大鼠的血糖水平降至正常水平。对照组、CTLA4Ig 转染组、CD40LIg 转染组和 CTLA4Ig+CD40LIg 共转染组的平均血糖水平分别在移植后第 8、24、21、68 天升高。对照组、CTLA4Ig 转染组、CD40LIg 转染组和 CTLA4Ig+CD40LIg 共转染组的移植物分别存活（8±1）、（29±4）、（27±3）和（74±10）天。CTLA4Ig+CD40LIg 共转染组的存活时间明显更长。CTLA4Ig 转染组和 CD40LIg 转染组的存活时间明显长于对照组。在对照组动物中，移植后 7 天内血清白细胞介素-2 和肿瘤坏死因子-α浓度显著升高。移植大鼠胰岛原位活组织检查未见炎性细胞浸润。免疫组织化学染色证实所有实验组胰岛均有胰岛素表达。
CTLA4Ig 和 CD40LIg 基因的转移，特别是两者的共转移，可抑制小鼠胰岛异种移植物的排斥反应。下调 Th1 细胞相关细胞因子的表达可能与这种有益作用有关。
