title: CD4+8- and CD4-8+ mature thymocytes require different post-selection processing for final development.
abstract: Two primary types of TCR-alpha/beta+ T cells are found in the peripheral lymphoid system; CD4+8- T cells, with MHC-class II restricted TCR, and CD4-8+ T cells, which are MHC-class I restricted. Both lineages develop in the thymus from a series of common precursors. However, the precise stage at which they diverge, and the combination of factors that regulates such divergence, are not well defined. The up-regulation of CD3/TCR to high mature levels is thought to be an early event associated with positive selection for self-MHC recognition. Using purified cells from bcl-2 transgenic mice in order to overcome the limitations imposed by cell death on normal thymocytes, we find that a minor subset of CD4+8+ thymocytes expressing high levels of CD3/TCR gives rise to both CD4+8- and CD4-8+ mature cells upon intrathymic transplantation, but only to CD4-8+ in culture. Thus, in addition to demonstrating the dual lineage potential of this subset, these findings show that additional post-selection processing events are required for the production of mature thymocytes, and that CD4+8- and CD4-8+ subsets differ in the types of processing required.
authors.affiliation: Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
authors.forename: H T
authors.initials: HT
authors.lastname: Petrie
authors.forename: A
authors.initials: A
authors.lastname: Strasser
authors.forename: A W
authors.initials: AW
authors.lastname: Harris
authors.forename: P
authors.initials: P
authors.lastname: Hugo
authors.forename: K
authors.initials: K
authors.lastname: Shortman
mesh_terms: D000818:Animals; D017252:CD3 Complex / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology*; D016827:CD8 Antigens / Q000276:immunology*; D002454:Cell Differentiation; D005260:Female; D005434:Flow Cytometry; D016130:Immunophenotyping; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D016176:T-Lymphocyte Subsets / Q000166:cytology*; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D017252:CD3 Complex; D016827:CD8 Antigens