title: CD1+ human thymocytes proliferate in response to superantigen staphylococcal enterotoxin B1.
abstract: Exposure of human thymocytes to superantigens results in the deletion of thymocytes expressing specific TCR-V beta genes. The factors that contribute to this deletion may relate to the inherent nature of the T cell at a given stage of development. In this paper, we demonstrate that CD1+ human cortical thymocytes are capable of proliferating in response to a bacterial superantigen (staphylococcal enterotoxin B (SEB)) in the presence of autologous CD2-/low thymic APCs. Phenotypic analysis of the responding populations revealed that the majority of the CD1+ cells were CD4+CD8low or CD8+CD4low cells. The response is triggered by low concentrations of SEB, requires the participation of the TCR and IL-2R molecules, and is inhibited by cyclosporin A. Thymocytes that express specific V beta genes are expanded, which results in an engagement profile that parallels that found in PBLs. Additionally, four V beta-chains that have not been reported previously are shown to engage SEB. Once stimulated, the thymocytes failed to respond to additional SEB; however, they could be induced to proliferative with IL-2, which suggests that these expanded populations had become anergic. These data represent the first demonstration of a human cortical thymocyte subpopulation that responds to superantigen by proliferation and subsequent anergy.
authors.affiliation: Department of Biology, San Diego State University, CA 92182.
authors.forename: S C
authors.initials: SC
authors.lastname: Todd
authors.forename: R
authors.initials: R
authors.lastname: Baccala
authors.forename: J A
authors.initials: JA
authors.lastname: Hedrick
authors.forename: A N
authors.initials: AN
authors.lastname: Theofilopoulos
authors.forename: C D
authors.initials: CD
authors.lastname: Tsoukas
mesh_terms: D015703:Antigens, CD / Q000276:immunology*; D018949:Antigens, CD1; D004306:Dose-Response Relationship, Immunologic; D004768:Enterotoxins / Q000276:immunology*; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D006801:Humans; D016130:Immunophenotyping; D007376:Interleukin-2 / Q000502:physiology; D008213:Lymphocyte Activation; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics; D013211:Staphylococcus aureus / Q000276:immunology*; D018089:Superantigens / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology
chemical_list: D015703:Antigens, CD; D018949:Antigens, CD1; D004768:Enterotoxins; D007376:Interleukin-2; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018089:Superantigens; C031818:enterotoxin B, staphylococcal