title: CD45RA antibodies split the CD3bright T cell subset.
abstract: Thymocyte subsets have been well characterized on the basis of CD4 and CD8 antigen expression. Recently, the use of anti-CD3 antibodies has allowed more precise phenotyping of these subsets. The most immature T cell precursors are largely CD3-CD4-CD8-, while the most mature are CD3brightCD4+CD8- or CD3brightCD4-CD8+. Moreover, the expression of CD45RA on thymocytes appears to define a progenitor population and may define a continuous lineage of cells. Using a panel of CD45RA antibodies, we have further characterized the CD45RA+ thymocyte population in the murine system. The size of this subset is greatly enhanced in cortisone-treated mice and in sublethally irradiated mice. Moreover, the CD45RA+ population is present early in foetal life and is maintained thereafter. Using three-colour immunofluorescence, we show that (i) while most CD45RA+ cells are present amongst the CD4-CD8- thymocyte subset in the normal thymus, after cortisone treatment or irradiation, all four thymocyte subsets co-express significant amounts of CD45RA. This suggests that not only progenitor cells but also the mature population which can survive such manipulation are CD45RA+; and (ii) a large proportion of CD45RA+ cells are CD3bright and this subset is represented in the thymus at all stages of maturation tested. These data suggest that a proportion of TCR-gamma delta + CD3+ cells in the fetus as well as of TCR-alpha beta+ CD3+ cells in the adult co-express CD45RA.
authors.affiliation: INSERM U 25, Hôpital Necker, Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Ezine
authors.forename: J
authors.initials: J
authors.lastname: Marvel
authors.forename: E
authors.initials: E
authors.lastname: Lightstone
authors.forename: N
authors.initials: N
authors.lastname: Dautigny
authors.forename: C
authors.initials: C
authors.lastname: Boitard
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000187:drug effects / Q000276:immunology*; D001788:Blood Grouping and Crossmatching; D017252:CD3 Complex; D015704:CD4 Antigens / Q000276:immunology; D016827:CD8 Antigens / Q000276:immunology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D006649:Histocompatibility Antigens / Q000276:immunology*; D006854:Hydrocortisone / Q000494:pharmacology; D017493:Leukocyte Common Antigens; D051379:Mice; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000187:drug effects / Q000276:immunology*; D013234:Stem Cells / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology*; D013950:Thymus Gland / Q000196:embryology* / Q000276:immunology; D014965:X-Rays / Q000009:adverse effects
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D006649:Histocompatibility Antigens; D011948:Receptors, Antigen, T-Cell; D017493:Leukocyte Common Antigens; D006854:Hydrocortisone