title: Surface antigens of human thymocyte populations defined by CD3, CD4 and CD8 expression: CD1a is expressed by mature thymocytes but not peripheral T cells.
abstract: Three colour flow cytometric analysis has been used to analyze the expression of a series of surface antigens on human thymic and peripheral T-cell populations. CD4, CD8 and CD3 were used to divide the populations into the conventional major categories, and the distribution of CD1a, CD2, CD7, CD34, CD44, class I MHC and class II MHC was then determined. Some characteristics of 'single positive' (CD4+8- and CD4-8+) T-lineage cells were unexpected. Amongst thymocytes, some 'immature single positives' were delineated as larger sized cells lacking cell surface CD3 and expressing low levels of class I MHC; however, in contrast with murine thymocytes, these were all CD4+8-, rather than being predominantly CD4-8+. Amongst peripheral T cells, a small proportion of CD7- cells were detected, within both the CD4+8-3+ and the CD4-8+3+ categories. Finally, in contrast to previous conclusions, CD1a was expressed at high levels on mature (CD4+8-3+ and CD4-8+3+) human thymocytes, although in agreement with previous reports it was absent from peripheral T cells. CD1a is therefore a useful marker of post-selection, post-thymic T-cell maturation.
authors.affiliation: Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.
authors.forename: F
authors.initials: F
authors.lastname: Sotzik
authors.forename: A
authors.initials: A
authors.lastname: Boyd
authors.forename: K
authors.initials: K
authors.lastname: Shortman
mesh_terms: D000293:Adolescent; D000328:Adult; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000096:biosynthesis*; D018949:Antigens, CD1; D017252:CD3 Complex / Q000096:biosynthesis; D015704:CD4 Antigens / Q000096:biosynthesis; D016827:CD8 Antigens / Q000096:biosynthesis; D002648:Child; D002675:Child, Preschool; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018949:Antigens, CD1; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I