title: Neonatal tolerance induction in the thymus to MHC-class II-associated antigens. IV. Significance of intrathymic chimerism of blood-born Ia+ cells in Mls tolerance.
abstract: The significance of thymus cell chimerism in the induction and maintenance of tolerance was investigated. Mls-1b BALB/c mice were neonatally tolerized by the intravenous administration of either bone marrow (BM) cells or peritoneal cavity (PerC) cells from Mls-1b/a (BALB/c x AKR) F1 mice. Tolerance was long-lasting in the BM cell group, but transient in the PerC cell group, probably because PerC cells lack hemopoietic stem cells required for a continuous supply of tolerance-inducing cells. The degree of anti-Mls-1a responsiveness of these BALB/c thymus cells was correlated with the degree of intrathymic distribution of the inoculated F1 cells. The effect of BM cell inoculation, resulting in a year-long deletion of Mls-1a-reactive V beta 6-bearing T cells is in marked contrast to that of PerC cell inoculation which causes only a transient loss of V beta 6+ mature thymocytes (for about 1 week after birth). This functional profile of the tolerant state correlates well with the degree and persistence of the intrathymic presence of F1 type Ia+ cells. The long-lasting presence of donor-derived cells throughout the thymus tissue in the BM cell group is also in marked contrast to the early disappearance of Ia+ cells (within 2-3 weeks) from the cortex and then from the medulla in the PerC cell group, although these Ia+ cells were once spread throughout the thymus tissue 4 days after the tolerance-inducing cell inoculation. Taken together with a failure to induce consistent unresponsiveness to Mls-1a determinants in Mls-1b thymocytes regenerating in Mls-1a-thymic epithelial environments, all the above data indicate that intrathymic chimerism caused by hemopoietic stem cell-derived MHC-class II-bearing cells is a requisite for the induction and maintenance of unresponsiveness by means of clonal deletion in experimentally as well as naturally induced tolerance to Mls determinants.
authors.affiliation: Department of Immunology, Kyoto University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hosono
authors.forename: M
authors.initials: M
authors.lastname: Kurozumi
authors.forename: M
authors.initials: M
authors.lastname: Inaba
authors.forename: S
authors.initials: S
authors.lastname: Ideyama
authors.forename: M
authors.initials: M
authors.lastname: Tomana
authors.forename: J
authors.initials: J
authors.lastname: Gyotoku
authors.forename: Y
authors.initials: Y
authors.lastname: Katsura
authors.forename: T
authors.initials: T
authors.lastname: Hosokawa
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology*; D016026:Bone Marrow Transplantation / Q000276:immunology; D004847:Epithelial Cells; D004848:Epithelium / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007108:Immune Tolerance; D007111:Immunity, Cellular; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D016747:Minor Lymphocyte Stimulatory Antigens; D010529:Peritoneal Cavity / Q000166:cytology; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016176:T-Lymphocyte Subsets / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology* / Q000637:transplantation; D013997:Time Factors
chemical_list: D000954:Antigens, Surface; D000949:Histocompatibility Antigens Class II; D016747:Minor Lymphocyte Stimulatory Antigens; D011948:Receptors, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta