title: Subpopulations of mature murine thymocytes: properties of CD4-CD8+ and CD4+CD8- thymocytes lacking the heat-stable antigen.
abstract: The heat-stable antigen (HSA), recognized by the monoclonal antibodies M1/69, B2A2, and J11d, is low or absent on the surface of most murine peripheral T cells but present on all but 3% of thymocytes. The CD4-CD8+ and CD4+CD8- or "single positive" thymic populations may be divided into further subgroups based on surface HSA expression. One group, CD4-CD8+ and expressing very high levels of HSA (HSA++), is an immature, T cell antigen receptor (TcR) negative, outer cortical blast cell. However, a further subdivision of CD4-CD8+ and CD4+CD8- single positives may be made, into those negative to low for HSA (HSA-) and those expressing moderate amounts of HSA (HSA+). The proportion of HSA- single positives is low in the thymus of young mice, whereas the proportion of HSA+ single positives is similar to that of the adult. Both the HSA- and the HSA+ subsets of single positive thymocytes from adult mice are CD3+ and express the normal peripheral T cell incidence of V beta 8 determinants on the TcR. On stimulation with concanavalin A in limit-dilution culture both HSA- and HSA+ subsets of single positive thymocytes give a high frequency of proliferating clones, and the clones from both HSA- and HSA+ subsets of CD4-CD8+ thymocytes are cytotoxic. Thus both HSA- and HSA+ single positive thymocytes are functionally mature. The HSA- subsets of single positive thymocytes differ from the HSA+ subsets in being slightly larger in size, in expressing higher levels of MEL-14, in binding more peanut agglutinin, and in including a proportion of cells expressing high levels of the Pgp-1 glycoprotein. It is suggested that HSA- CD4-CD8+ and HSA- CD4+CD8- thymocytes are more mature than their HSA+ counterparts, and might represent a previously activated or "memory" thymic subpopulation.
authors.affiliation: Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Wilson
authors.forename: L M
authors.initials: LM
authors.lastname: Day
authors.forename: R
authors.initials: R
authors.lastname: Scollay
authors.forename: K
authors.initials: K
authors.lastname: Shortman
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis* / Q000096:biosynthesis / Q000502:physiology; D000954:Antigens, Surface / Q000096:biosynthesis / Q000502:physiology*; D002454:Cell Differentiation; D002470:Cell Survival; D003165:Complement System Proteins / Q000276:immunology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006358:Hot Temperature; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000145:classification / Q000166:cytology / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000145:classification / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000145:classification / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D011948:Receptors, Antigen, T-Cell; D003165:Complement System Proteins