Regulation of the expression of immature thymocyte antigen-1 (IMT-1) during T-cell development in thymus

之前。我们生产了一种识别未成熟胸腺细胞抗原-1 （IMT- 1）的单克隆抗体。IMT- 1在胸腺细胞上的表达从CD4^-CD8^-分化后期到CD4^+CD8^+分化后期。当CD4^+CD8^+胸腺细胞分化为CD^++8^+或CD4^-8^+细胞时，IMT-1从细胞表面消失（Kishi et aL， J.Immunol.）。[j]。在这项研究中。我们研究了TCR信号对IMT- 1表达的调控。分析t细胞受体（T-cell-receptor， TCR）转基因小鼠胸腺细胞上IMT- 1的表达，发现在接受阳性或阴性选择信号的胸腺细胞上IMT- 1的表达降低。此外，当抗cd3抗体刺激甲状腺细胞时，CD4^+CD8^+胸腺细胞上的IMT- 1表达降低。这些结果表明IMT- 1在CD4^+CD8^+胸腺细胞上的表达是通过alphabetaTCR信号调节的（Kishi et aL, Int.）。Immunol。[j] .农业科学，1998(10):951-960。然后我们检测了预tcr对IMT- 1表达的影响。研究发现，在胎儿胸腺细胞发育过程中，pre-TCR和IMT- 1在胎儿胸腺细胞上协调表达，并且anti-CD3抗体刺激RAG2^-/^-胸腺细胞具有相应的动力学，从而下调pre-TCR和IMT- 1 （Tong et aL, immuno1）。农业学报，96:48-56,1999)。这些数据表明，在胸腺t细胞发育过程中，IMT-1的表达受到TCR前和TCR信号的调控，表明IMT-1参与了t细胞的发育。

Previously. we produced a monoclonal antibody that recognizes immature thymocyte antigen-1 (IMT- 1). IMT- 1 is expressed on thymocytes from the late differentiation stage of CD4^-CD8^- to that of CD4^+CD8^+. When CD4^+CD8^+ thymocytes differentiate into CD^++8^+ or CD4^-8^+ cells, IMT-1 disappears from the cell surface (Kishi et aL, J.Immunol. . 155 : 568-577, 1995). In this study. we Investigated the regulation of IMT- 1 expression by TCR signaling. When the expression of IMT- 1 on thymocytes in T-cell-receptor (TCR) transgenic mice was analyzed, IMT- 1 expression was found to be decreased on thymocytes that received signals inducing positive or negative selection. Furthermore, IMT- 1 expression on CD4^+CD8^+ thymocytes was reduced, when thyrnocytes were stimulated by anti-CD3 antibody. These results Indicate that IMT- 1 expression on CD4^+CD8^+ thymocytes is regulated by signals through alphabetaTCR (Kishi et aL, Int. Immunol., 10 : 951-960, 1998). Then we examined the effect of pre-TCR on the expression of IMT- 1 . It was observed that pre-TCR and IMT- 1 is coordinately expressed on fetal thymocytes durIng fetal thymocyte development and that pre-TCR and IMT- 1 were downregulated by the stimulation of RAG2^-/^- thymocytes with anti-CD3 antibody with corresponding kinetics (Tong et aL, Immunol., 96 : 48-56, 1999). These data demonstrate that during T-cell development in thymus, LMT-1 expression Is regulated by the signals through pre-TCR as well as TCR and indicate the involvement of IMT-1 in T-cell development.