肝特异性抗原的同种异体免疫原性

The alloimmunogenicity of liver specific antigen

目的 研究肝特异性抗原的同种异体免疫原性及其意义。方法 用近交系F3 44大鼠的肝特异性抗原作为免疫原 ,通过小剂量长期足垫免疫、门静脉及胸腺大剂量免疫等不同的方法免疫近交系Lew大鼠 ,以环磷酰胺 15 0mg/kg腹腔注射作为诱导淋巴细胞凋亡的阳性对照 ,用混合淋巴细胞 (MLC)培养、混合淋巴细胞肝细胞 (MLHC)培养、Western印迹、DNA凝胶电泳分析及TUNEL等检测手段 ,对外周及中枢淋巴器官的功能进行分析 ,以确定免疫后机体的免疫状态。结果 在取材时间点 ,各实验组均出现不同程度的特异性低免疫应答 :MLC变化不明显 ,但MLHC却均较对照组明显降低 ,而各实验组Caspase 3的表达均明显增高 ,脾细胞的DNA凝胶电泳表现出抗原特异性的淋巴细胞凋亡 ,胸腺TUNEL结果 ,各实验组均出现不同程度的凋亡细胞。结论 肝特异性抗原具有同种异体免疫原性 ,可能是一种重要的移植抗原 ,为诱导同种移植免疫耐受开拓新的途径 ;对移植肝或细胞免疫原性的调变 ,不但要针对同种异体主要组织相容复合物 (MHC)抗原 。

Objective To investigate the alloimmunogenicity of liver specific antigen and its significance. Methods Liver specific antigen isolated from inbred F344 rats was used as immunogen to immunize inbred Lew rats through different immunization pathways such as low-dose long-term hindfoot pads, high-dose portal vein and thymus immunization. Rats receiving 150?mg/kg cyclophosphamide by intraperitoneal route were used as positive control of lymphocyte apoptosis. Mixed lymphocyte culture, mixed lymphocyte hepatocyte culture, Western blotting, DNA gel electrophoresis and TUNEL were employed to analyze the status of peripheral and central lymphoid organs. Results At the time points of sampling, varying degrees of specific low immunoresponses appeared in all immunized groups as well as CY treated group. Compared with groupⅠ, MLC of the experimental groups had no significant changes except that of group Ⅴ, whereas MLHC decreased remarkblely. In all experimental groups, the expression levels of Caspase-3 were increased significantly, splenocytes indicated specific lymphocyte clone apoptosis, and apoptotic cells were also detected in thymus. Conclusions Liver specific antigen has alloimmunogenicity. It may be an important transplantation antigen which may lead to a novel way to liver transplantation immunotolerance. Attempts to modulate immunogenicity of liver allografts or grafted hepatocytes should be direct not only toward the allogenic MHC antigens but also toward allogenic non-MHC antigens.