天花粉蛋白引起个体间CD8细胞负调节功能差异性表达的免疫学机制

在天花粉蛋白 (Tk )作用下 ,正常人群可因CD8细胞是否显示负向调节作用而分为介导型 (M+)和非介导型 (M-)两类 ,并作为一对遗传性状受HLA DQ基因调控。本研究表明 ,M-个体CD8细胞丧失抑制活性是因为激活了一群CD8VV+反抑制T细胞 (Tcs) ,而Tcs的激活可能依赖于CD4阳性诱导细胞的存在。由于Tk可以在M-个体中却不能在M+个体中激活这一诱导细胞 ,造成只有前者出现CD8Tcs及特定的应答格局。由此推论 ,DQ基因对Tk相关免疫抑制的调节点在Tcs的诱导水平。

The Immunological Mechanisms Underlying the Trichosanthin-induced Differential Expression of the Down Regulatory Activity of CD8 T Cells Between Subjects Defined as CD8-mediators (M+) and Non-mediators (M-)

Our previous work showed that healthy subjects can be divided into CD8 cell mediators (M ) and non mediators (M -) according to whether their CD8 cells are able to down regulate immune responses under the influence of Trichosanthin, a plant protein isolated from a Chinese medicinal herb, and that the traits M /M - are inherited in association with HLA DQ genes In this study, data reveal that the failure of M - subjects'CD8 cells to induce suppression was attributable to the activation of a CD8 contrasuppressive T subset with Vicia vilosa lectin receptor (CD8VV Tcs) And the activation of the Tcs might be dependent on the appearance of CD4 inducer cells, which could only exert their role in M - instead of M subjects in case Tk was presented Based upon these results, we propose that the DQ genes that determine the phenotype M might work at the Tcs inducing level via certain CD4 positive T cells