title: Peripheral NK1.1 NKT cells are mature and functionally distinct from their thymic counterparts.
abstract: One interesting aspect of NKT cell development is that although they are thymus dependent, the pivotal transition from NK1.1(-) to NK1.1(+) can often take place after immature NK1.1(-) NKT cells are exported to the periphery. NK1.1(-) NKT cells in general are regarded as immature precursors of NK1.1(+) NKT cells, meaning that peripheral NK1.1(-) NKT cells are regarded as a transient, semimature population of recent thymic emigrant NKT cells. In this study, we report the unexpected finding that most NK1.1(-) NKT cells in the periphery of naive mice are actually part of a stable, mature and functionally distinct NKT cell population. Using adult thymectomy, we show that the size of the peripheral NK1.1(-) NKT cell pool is maintained independently of thymic export and is not the result of NK1.1 down-regulation by mature cells. We also demonstrate that most peripheral NK1.1(-) NKT cells are functionally distinct from their immature thymic counterparts, and from NK1.1(+) NKT cells in the periphery. We conclude that the vast majority of peripheral NK1.1(-) NKT cells are part of a previously unrecognized, mature NKT cell subset.
authors.affiliation: Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Finlay W
authors.initials: FW
authors.lastname: McNab
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Pellicci
authors.forename: Kenneth
authors.initials: K
authors.lastname: Field
authors.forename: Gurdyal
authors.initials: G
authors.lastname: Besra
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Smyth
authors.forename: Dale I
authors.initials: DI
authors.lastname: Godfrey
authors.forename: Stuart P
authors.initials: SP
authors.lastname: Berzins
mesh_terms: D000818:Animals; D000950:Antigens, Ly; D000954:Antigens, Surface / Q000096:biosynthesis / Q000276:immunology*; D015536:Down-Regulation / Q000276:immunology*; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D037181:Lectins, C-Type / Q000096:biosynthesis / Q000276:immunology*; D051379:Mice; D055651:NK Cell Lectin-Like Receptor Subfamily B; D009928:Organ Specificity / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000254:growth & development / Q000276:immunology* / Q000378:metabolism
chemical_list: D000950:Antigens, Ly; D000954:Antigens, Surface; C527211:Klrb1c protein, mouse; D037181:Lectins, C-Type; D055651:NK Cell Lectin-Like Receptor Subfamily B