| Project/Area Number |
62480167
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | Kyushu University |
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Principal Investigator |
YOSHIKAI Yasunobu Medical Institute of Bioregulation, Kyushu University, Associate Professor, 生体防御医学研究所, 助教授 (90158402)
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| Co-Investigator(Kenkyū-buntansha) |
TANIGUCHI Kazuto Medical Institute of Bioregulation, Kyushu University, Assistant Professor, 生体防御医学研究所, 助手 (50117165)
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| Project Period (FY) |
1987 – 1989
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| Keywords | T cells / T cell receptor / T cell differentiation / Thymus / bone marrow chimera / Thymus-grafted nude mice |
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| Research Abstract |
T cell precursors derived from hematopoietic stem cells proliferate and differentiate in thymus, where T cells with self-MHC specificities are positively selected (positive selection) and T cells with a high affinities for self-antigens are tolerized(negative selection). These selections are carried out on the basis of their T cell receptors (TcR). To elucidate the molecular mechanism of T cell differentiation, we have investigated the expression of TcR gene in bone marrow(BM), thymus and peripheral lymphoid tissues of mice.
1. BM --- The use of the long-term cultured bone marrow (LTBM) cells provided a pertinent source of cells for investigating the early phase of T cell differentiation before migration to the thymus. Our study with athymic nde mice and 1pr/1pr mice indicated abnormal rearrangememnts of TcR genes in the LTBM cells, suggesting that T cell precursors in BM of these mice may be different in quantity and/or quality from those in normal mice.
2. Thymus --- Radiation BM chimeras have been used as an experimental model for investigation of mechanisms of selective events in thymxis of adult mice. We have found that both T cells bearing TcR capable of recognizing host- and donor phenotypes are deleted in the thymus of radiation BM chimeras.
3. Peripheral lymphoid tissues --- The cellular basis of tolerant induction has been investigated in nude mice grafted with fetal thymus. Thymic epithelium have a capacity to induce tolerance to MHC class II but not to Mls-encoded antigens.
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