title: Thymic shared antigen-1. A novel thymocyte marker discriminating immature from mature thymocyte subsets.
abstract: In a previous study, we raised a mAb (MTS 35) reacting with a plasma membrane Ag expressed on both cortical thymocytes and a subset of thymic medullary epithelial cells. In view of the shared expression of this molecule, we have defined it as thymic shared Ag-1 (TSA-1). Considering its selective reactivity with cortical, but not medullary thymocytes, the relevance of TSA-1 as a marker of immature T cells was investigated in detail in this study, using multicolor flow cytometric analysis. TSA-1 was found on all immature thymocyte subsets (CD3-4-8-, CD3-4+8-, CD3-4-8+, CD3-4+8+, CD3low4+8+). Conversely, CD3high4+8- and CD3high4-8+ thymocytes, early thymic migrants and peripheral T cells were TSA-1-. More refined gating and analysis of the transitional CD3intermediate/high4+8+ thymocytes, proposed candidates for negative selection, demonstrated that approximately one half were TSA-1-. In fact, there was a directly inverse relationship between TSA-1 and CD3 expression on thymocytes. In the periphery, TSA-1 was detected on B lymphocytes. TSA-1 is PI-linked and has a molecular mass of 17 kDa nonreduced, or 12 to 13 kDa reduced. Through cross-correlation analysis, this molecule was distinct from H-2K, PNA-R, CD5, CD11a/18, Thy-1, HSA, Ly6A/E, Ly6C, ThB, CD25, CD44. Hence TSA-1 appears to be a unique marker which exquisitely separates mature from immature thymocytes.
authors.affiliation: Department of Pathology and Immunology, Monash University Medical School, Melbourne, Victoria, Australia.
authors.forename: D I
authors.initials: DI
authors.lastname: Godfrey
authors.forename: M
authors.initials: M
authors.lastname: Masciantonio
authors.forename: C L
authors.initials: CL
authors.lastname: Tucek
authors.forename: M A
authors.initials: MA
authors.lastname: Malin
authors.forename: R L
authors.initials: RL
authors.lastname: Boyd
authors.forename: P
authors.initials: P
authors.lastname: Hugo
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis*; D001402:B-Lymphocytes / Q000276:immunology; D017252:CD3 Complex; D005260:Female; D051379:Mice; D008808:Mice, Inbred CBA; D016513:Mice, SCID / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D010738:Type C Phospholipases / Q000494:pharmacology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D017252:CD3 Complex; D011948:Receptors, Antigen, T-Cell; D010738:Type C Phospholipases