胸腺内T細胞分化に関与する上皮細胞表面分子の解析

点击翻译按钮获取中文摘要

Previously we reported a novel thymic stromal cell antigen, HS9, as a potent molecule participating in intrathymic T cell development. HS9 antigen is expressed on thymic stromal cells especially in the cortex but out on thymocytes. In the present study, we isolated and characterized a novel cDNA,N14, encoding HS9 antigen. Sequencing analysis of N14cDNA has revealed it to be a nocel one without any significant homology to previously reported functional molecules. COS7 cells transfected with expression vectors harboring N14 cDNA became reactive with HS9-specific mAb. Northern blot analysis and in situ hybridization revealed that several tissues, which are positive for HS9 mAb, expressed N14 mRNA.In order to examine the role of this molecule in T cell development, transgenic mice were generated. In situ hybridization study showed that the transgene was significantly over-expressed on both cortical and medullar thymic stromal cells but not on thymocytes. Flowcytometric analysis showed that the percentage of mature CD4^-CD8^+ or CD4^+CD8^- thymocytes of transgenic mice were approximately twice and triple, respectively, than control littermates. Moreover, substantial CD4^+CD8^+ thymocytes appeared to be TCRhigh as comparable to peripheral T cells. Histological examination revealed that trangenic mice had thin cortex and relatively developed medulla. These data indicate the critical role of the N14 gene in T cell development.