title: Regulation of early T cell development by the engagement of TCR-beta complex expressed on fetal thymocytes from TCR-beta-transgenic scid mice.
abstract: Transgenic expression of the beta-chain of T cell antigen-receptor (TCR) is known to induce the generation of CD4+ CD8+ thymocytes in the immunodeficient scid mouse, in which thymocyte development is otherwise arrested at CD4- CD8- cells. It is not clear, however, whether or not the thymocyte development is controlled by ligand engagement of the TCR-beta complex on the cell surface. In the present study, we have examined how the engagement by Ab of the TCR-beta complex expressed on the TCR-beta-transgenic scid fetal thymocytes can regulate the generation of CD4+ CD8+ thymocytes. Organ cultures of CD4- CD8- day 14 fetal thymocytes from the TCR-beta-transgenic scid mice resulted in the generation of CD4- CD8+ and then CD4+ CD8+ cells. The initial step from CD40- CD8- cells to CD4- CD8+ cells was enhanced by the addition of anti-TCR-beta Ab, whereas the subsequent step from CD4- CD8+ cells to CD4+ CD8+ cells was markedly inhibited by anti-TCR-beta Ab. These results indicate that ligand engagement of the TCR-beta complex can positively and negatively regulate the early thymocyte development. Moreover, the finding that engagement of TCR-beta complex inhibits the generation of CD4+ CD8+ cells suggests that the induction of CD4+ CD8+ thymocytes by the TCR-beta transgene is not an immediate consequence of cell-surface engagement of the TCR-beta complex but requires liberation from the continued TCR-beta signaling.
authors.affiliation: Institute of Immunology, Syntex, Ibaraki, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Takahama
authors.forename: K
authors.initials: K
authors.lastname: Sugaya
authors.forename: S
authors.initials: S
authors.lastname: Tsuda
authors.forename: T
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Y
authors.initials: Y
authors.lastname: Hashimoto
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001483:Base Sequence; D002454:Cell Differentiation; D002478:Cells, Cultured; D005434:Flow Cytometry; D051379:Mice; D016513:Mice, SCID; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009924:Organ Culture Techniques; D016133:Polymerase Chain Reaction; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology* / Q000196:embryology
chemical_list: D000911:Antibodies, Monoclonal; D016693:Receptors, Antigen, T-Cell, alpha-beta