CTLA4-Ig对肝细胞移植大鼠免疫耐受的作用及其机制

目的 探讨细胞毒性淋巴细胞相关抗原4融合蛋白(CTLA4-Ig)诱导肝细胞移植大鼠免疫耐受的作用及机制.方法 10%D-氨基半乳糖(D-gal)一次性腹腔注射建立大鼠急性药物性肝衰竭模型;采用肝脏原位灌注法分离纯化肝细胞,经脾脏移植后随机分为两组.实验组腹腔一次性注射CTLA4-Ig,对照组不予处理.两组均分别于术后第1、3、5、7天采外周血观察白细胞介素(IL)-2、肿瘤坏死因子(TNF)及肝功能变化;术后1周测两组大鼠外周血T细胞亚群,处死大鼠后取脾脏苏木素-伊红(HE)染色.结果 实验组谷丙转氨酶(ALT)、血清总胆红素(TBil)于术后第7天分别为(6.5±7.3)IU/ml、(5.1±1.6)mmol/L,低于对照组.术后治疗组IL-2含量明显下降,第7天达到(1. 3138±0.8508)ng/L,两组差异有统计学意义(P＜0.05);术后TNF含量两组之间差异无统计学差异(P＞0.05).外周血CD4+T细胞、CD4+/CD8+T细胞实验组分别为(37.3±7.2)%、(1.5±0.1)%,低于对照组(P＜0.05),CD8+T细胞两组差异无统计学意义(P＞0.05).术后第7天治疗组脾内仍可见肝细胞或肝细胞团,对照组见大量淋巴细胞浸润,但很少见肝细胞.结论 CTLA4-Ig能诱导经脾同种异体肝细胞移植大鼠免疫耐受,使急性肝衰大鼠肝功能得到改善.可能是抑制T淋巴细胞亚群,且主要是抑制CD4+T细胞,使CD4+/CD8+T细胞比值下降;抑制IL-2的分泌.

Abstract：

Objective To investigate the immunosuppressive effect of cytotoxic T Iymphocyte associated antigen 4 Ig fusion protein (CTLA4-Ig) in rat allograft hepatocyte transplantation model and the mechanisms. Methods Acute liver failure (ALF) model was established by intraperitoneal injection of 10% D-gal solution to SD rates. Collagenase perfusion was performed on SD rats to separate liver cells. SD rats with ALF were subjected to intrasplenic hepatocyte transplantation and randomly divided into two groups. The experimental group received intraperitoneal injection of CTLA4-Ig. The concentrations of interleukin (IL)-2 and tumor necrosis factor (TNF), liver function and histologicy were observed at the 1st,3rd, 5th, 7th day after operation and the T lymphocyte subsets were detected by using immunohistochemistry at the 7th day after operation. Results The levels of ALT and TBil were respectively (6. 5 ±7.3) IU/ml and (5.1 ± 1.6) mmol/L at the 7th day after operation and significantly decreased after injection of CTLA4-Ig ( P ＜ 0. 01 ). IL-2 concentration in the experimental group was ( 1.3138 ± 0. 8508 ) ng/L at the 7th day after operation and significantly decreased (P ＜0. 05). TNF had no significant difference between two groups after operation ( P ＞ 0. 05 ). T lymphocyte subsets, mainly CD4 + , in the experimental group was significantly decreased as compared with control group ( P ＜ 0. 05 ), so did the CD4 +/CD8 +. Histological changes: At the 7th day after operation, there were some hepatocytes in the spleen of the experimental group. But in the control group, the changes in the spleen were characterized by severe lymphocyte infiltration. There were no hepatocytes both groups. Conclusion CTLA4-Ig can induce rat allogeneic hepatocytes intrasplenic transplantation immune tolerance. It may improve the liver function of rats with ALF.CTLA4-Ig can decrease T lymphocyte subsets, mainly CD4 + and concentrations of IL-2.

Rat allogeneic hepatocyte transplantation immune tolerance induced by CTLA4-Ig

Objective To investigate the immunosuppressive effect of cytotoxic T Iymphocyte associated antigen 4 Ig fusion protein (CTLA4-Ig) in rat allograft hepatocyte transplantation model and the mechanisms. Methods Acute liver failure (ALF) model was established by intraperitoneal injection of 10% D-gal solution to SD rates. Collagenase perfusion was performed on SD rats to separate liver cells. SD rats with ALF were subjected to intrasplenic hepatocyte transplantation and randomly divided into two groups. The experimental group received intraperitoneal injection of CTLA4-Ig. The concentrations of interleukin (IL)-2 and tumor necrosis factor (TNF), liver function and histologicy were observed at the 1st,3rd, 5th, 7th day after operation and the T lymphocyte subsets were detected by using immunohistochemistry at the 7th day after operation. Results The levels of ALT and TBil were respectively (6. 5 ±7.3) IU/ml and (5.1 ± 1.6) mmol/L at the 7th day after operation and significantly decreased after injection of CTLA4-Ig ( P ＜ 0. 01 ). IL-2 concentration in the experimental group was ( 1.3138 ± 0. 8508 ) ng/L at the 7th day after operation and significantly decreased (P ＜0. 05). TNF had no significant difference between two groups after operation ( P ＞ 0. 05 ). T lymphocyte subsets, mainly CD4 + , in the experimental group was significantly decreased as compared with control group ( P ＜ 0. 05 ), so did the CD4 +/CD8 +. Histological changes: At the 7th day after operation, there were some hepatocytes in the spleen of the experimental group. But in the control group, the changes in the spleen were characterized by severe lymphocyte infiltration. There were no hepatocytes both groups. Conclusion CTLA4-Ig can induce rat allogeneic hepatocytes intrasplenic transplantation immune tolerance. It may improve the liver function of rats with ALF.CTLA4-Ig can decrease T lymphocyte subsets, mainly CD4 + and concentrations of IL-2.