title: Differentiation in vitro of Lyt 2+ thymocytes from embryonic Lyt 2- precursors.
abstract: In mice, the thymus is regarded as being the primary anatomical site for the generation of immunologically competent T lymphocytes. Such cells comprise approximately 20% of the cells in the thymus and share with T lymphocytes from peripheral lymphoid tissues certain phenotypic properties defined by anti-Lyt antibodies. Thus, most immunocompetent T cells are either Lyt 1+2+ or Lyt 1+2- with the former cells being restricted to recognizing antigen in association with class I (H-2K, D) major histocompatability complex (MHC) products and the latter to class II (H-21) MHC products. Although evidence suggests that Lyt 1+2+ cells are generated from Lyt 1+2- precursor the independent development of two separate Lyt-defined lineages of thymocytes could not be ruled out. Here, the acquisition of Lyt 2 antigen by Lyt 2- cells from late embryonic and early postnatal thymuses is directly demonstrated. Furthermore, by combining cell cycle and Lyt phenotype analysis on a flow microfluorometer, the role of cell division in this differentiation process has been investigated.
mesh_terms: D000367:Age Factors; D000818:Animals; D000950:Antigens, Ly / Q000032:analysis*; D002453:Cell Cycle; D002454:Cell Differentiation; D002478:Cells, Cultured; D051379:Mice; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000196:embryology
chemical_list: D000950:Antigens, Ly