大鼠同种肝移植免疫耐受机制的研究

Experimental study on the immunological tolerance in rat liver transplantation

目的:探讨与大鼠肝移植免疫耐受相关的细胞学改变。方法:分析从肝移植物分离出的移植物浸润细胞(GIC)的表现型和功能,同时比较长期生存的BN→LEW模型和急性排斥反应的DA→LEW模型。结果:通过流式细胞仪计数确定DA→LEW受体的T细胞和激活的T细胞相对比例高于BN→LEW受体;移植后第7、14和30天,GIC表现型证实所有T细胞、OX8阳性细胞(细胞毒T细胞和NK细胞)和OX39阳性细胞(IL-2受体)的相对比例在移植后第7天最高,移植后30d下降;移植后第7天急性排斥反应时GIC细胞毒T细胞活性高于长期生存者。结论:移植后第7天免疫抑制机制已存在;在长期生存的肝移植物中细胞毒T细胞的激活和浸润均受到抑制。

Objective To elucidate the immunological characteristics of rat liver transplantation. Methods The graft-infiltrating cells （GIC） isolated from rat hepatic allografts were analyzed phenotypically and functionally. GIC from long-surviving recipients （Brown Norway livers into Lewis hosts） were compared with the acutely rejecting recipients （DA livers into Lewis hosts）. Results The relative proportions of all the T cells and the activated T cells determined by flow cytometry were significantly higher in the acutely rejecting Lewis recipients than in the long-surviving recipients on day 7 after grafting. The phenotypic analysis of GIC on day 7, 14 and 30 after transplantation from long-surviving Lewis hosts showed that each proportion of all the T cells, the OX8-positive cells （cytotoxic T and natural killer cells） and the OX39- positive cells （IL-2 receptor） was the greatest on day 7 and decreased on day 30. The cytotoxic activity of GIC toward donor lymphocytes on day 7 was greater in the acutely rejecting than that in the long-surviving recipients. Conclusions The immunosuppressive mechanism is already present on day 7 posttransplantation, and the infiltration or activation of the cytotoxic T cells is inhibited in the long-surviving rat hepatic allografts.