title: A novel cell surface antigen, immature thymocyte antigen-1, is involved in the differentiation of murine thymocytes.
abstract: A mAb, 1-23, which recognizes a novel cell surface Ag on immature murine thymocytes (designated as IMT-1 for immature thymocyte antigen-1) was prepared. IMT-1 was found to be expressed on 40 to 50% of CD4-8- double negative (DN), 5 to 10% of CD4-8+, and 5 to 20% of CD4+8+ double positive (DP) thymocytes in adult mice, but not expressed on CD4+8- thymocytes or peripheral T lymphocytes. It was not expressed on either nonlymphoid cell lines or thymic stromal cells. In subsets of DN thymocytes, IMT-1 was detected on 40 to 50% of the heat-stable Ag+, 15% of CD44+25+, 70% of CD44-25+, and 70% of CD44-25- populations, whereas it was not detected on heat-stable Ag- and CD44+25- populations. IMT-1+ thymocytes expressed low levels of or no CD3 molecules. In fetal thymuses, IMT-1 was expressed on a minor population of thymocytes at day 14.5 and 15.5 of gestation. However, at day 16.5 of gestation, a majority of DN as well as DP thymocytes became IMT-1-positive. Addition of the 1-23 Ab to the fetal thymus organ culture relatively increased CD8+ SP thymocytes. These results show that IMT-1 is expressed during the late DN stage as well as the early DP stage of thymocyte maturation and suggest the possible involvement of IMT-1 in thymocyte differentiation.
authors.affiliation: Department of Immunology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kishi
authors.forename: D M
authors.initials: DM
authors.lastname: Su
authors.forename: A
authors.initials: A
authors.lastname: Muraguchi
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D016516:CD4-CD8 Ratio; D002454:Cell Differentiation / Q000276:immunology*; D005314:Embryonic and Fetal Development; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009924:Organ Culture Techniques; D011247:Pregnancy; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; C120077:immature thymocyte-specific antigen, IMT-1