| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
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.
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