title: Distinct sequence of negative or positive selection implied by thymocyte T-cell receptor densities.
abstract: Recent evidence suggests that positive and negative selection of thymocytes bearing alpha beta T-cell receptors occurs during the predominant double-positive (CD4+CD8+) stage. But the sequence or stage at which positive or negative selection occurs during thymocyte maturation has not been well defined. Here we use transgenic mice to show that the CD4+CD8+ stage might be further subdivided into CD3lo (low) and CD3in (intermediate) stages. The CD3in stage could represent T cells that have been positively selected, as this stage is dependent on the presence of the appropriate major histocompatibility complex restriction element. In addition, we use two different tolerizing antigens to show that negative selection may occur either before or after this CD3in stage.
authors.affiliation: Department of Experimental Pathology, University Hospital, Zürich, Switzerland.
authors.forename: P S
authors.initials: PS
authors.lastname: Ohashi
authors.forename: H
authors.initials: H
authors.lastname: Pircher
authors.forename: K
authors.initials: K
authors.lastname: Bürki
authors.forename: R M
authors.initials: RM
authors.lastname: Zinkernagel
authors.forename: H
authors.initials: H
authors.lastname: Hengartner
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000032:analysis / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis / Q000276:immunology; D017252:CD3 Complex; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D006183:H-2 Antigens / Q000235:genetics / Q000276:immunology; D006239:Haplotypes; D007108:Immune Tolerance; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000032:analysis / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D006183:H-2 Antigens; D011948:Receptors, Antigen, T-Cell