title: Alpha beta lineage-committed thymocytes can be rescued by the gamma delta T cell receptor (TCR) in the absence of TCR beta chain.
abstract: Commitment of the alpha beta and gamma delta T cell lineages within the thymus has been studied in T cell receptor (TCR)-transgenic and TCR mutant murine strains. TCR gamma delta-transgenic or TCR beta knockout mice, both of which are unable to generate TCR alpha beta-positive T cells, develop phenotypically alpha beta-like thymocytes in significant proportions. We provide evidence that in the absence of functional TCR beta protein, the gamma delta TCR can promote the development of alpha beta-like thymocytes, which, however, do not expand significantly and do not mature into gamma delta T cells. These results show that commitment to the alpha beta lineage can be determined independently of the isotype of the TCR, and suggest that alpha beta versus gamma delta T cell lineage commitment is principally regulated by mechanisms distinct from TCR-mediated selection. To accommodate our data and those reported previously on the effect of TCR gamma and delta gene rearrangements on alpha beta T cell development, we propose a model in which lineage commitment occurs independently of TCR gene rearrangement.
authors.affiliation: Section of Immunobiology, Yale University School of Medicine, New Haven, USA.
authors.forename: F
authors.initials: F
authors.lastname: Livák
authors.forename: A
authors.initials: A
authors.lastname: Wilson
authors.forename: H R
authors.initials: HR
authors.lastname: MacDonald
authors.forename: D G
authors.initials: DG
authors.lastname: Schatz
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D015332:Gene Rearrangement, alpha-Chain T-Cell Antigen Receptor / Q000276:immunology; D051379:Mice; D008806:Mice, Inbred AKR; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D018448:Models, Immunological; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000502:physiology*; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D019076:Transgenes / Q000276:immunology
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta