CTLA4-Ig基因对大鼠肝移植后免疫细胞浸润及细胞凋亡的影响

目的研究腺病毒介导的细胞毒性T淋巴细胞相关抗原4-Ig(cytolyticT-lymphocyteassociatedantigen4-Ig,CTLA4-Ig)基因对大鼠肝移植后移植物中免疫细胞浸润和细胞凋亡的影响。方法将大鼠原位肝移植模型分为排斥对照组、环孢素A(CsA)组和CTLA4-Ig组。分别于术后1,3,5,7,12d,用免疫组织化学法和缺口末端标记技术(TUNEL法)分别测定移植物中CTLA4-Ig基因的表达和巨噬细胞、CD8 T细胞浸润及细胞凋亡,并以病理形态学变化作参照。结果静脉注射重组CTLA4-Ig基因腺病毒7d后,大鼠肝脏CTLA4-Ig稳定表达,在肝移植60d后仍呈阳性;CTLA4-Ig组汇管区巨噬细胞、CD8 T细胞浸润明显较排斥对照组少;细胞凋亡指数在术后3、5和7d明显低于排斥对照组(P<0·01),汇管区巨噬细胞、CD8 T细胞浸润数和凋亡指数与排斥反应分级均显著相关。结论重组CTLA4-Ig基因腺病毒经静脉一次给药后能在大鼠肝脏稳定表达,并通过抑制移植物中免疫细胞浸润及移植物细胞凋亡,抑制移植后急性排斥反应。

Role of adenovirus mediated CTLA4-Ig gene in the immune cells infiltration and cell apoptosis in murine liver transplantation

Objective To investigate the role of B7/CD28 costimulation pathway blockade with adenovirus-mediated CTLA4-Ig gene in macrophage and CD8~ T cell infiltration and cell apoptosis in murine liver transplantation. Methods Rat pairs were divided into three groups: SD-to-Wistar transplantation control group, CsA-treated group and CTLA4-Ig-treated group. IHC and TUNEL were used to analyze the expression of CTLA4-Ig gene in liver and immune cells infiltrate and cell apoptosis in liver grafts. Pathology was done on all harvested grafts. ResultsCTLA4-Ig gene expression was positive in the donor liver on day 7 after administering adenovirus-mediated CTLA4-Ig gene via vein, and remained positive until day 60 after liver transplantation. Infiltration of immune cells in CTLA4-Ig-treated group was less than that in rejection control group. the apoptotic index of rejection group on day 3,5,7 was significantly higher than those of CTLA4-Ig-treated. Conclusions CTLA4-Ig gene was constantly expressed in the donor liver after single intravenousely injection into rats using adenovirus as vector. Adenovirus-mediated CTLA4-Ig gene therapy can inhibit infiltration of immune cells and apoptosis in grafts, thus prolonging the survival of recipients.