title: CD4 engagement by CD1d potentiates activation of CD4+ invariant NKT cells.
abstract: The CD4 coreceptor is crucial in the activation of major histocompatibility complex (MHC) class II restricted CD4 (+) T lymphocytes by binding the same MHC class as the T-cell receptor (TCR) and by potentiating TCR-dependent signaling. CD4 is also expressed by invariant natural killer T cells (iNKT), which recognize natural and synthetic lipid antigens, such as alpha-galactosyl ceramide (alpha-GalCer), in association with the MHC class I-like CD1d molecule. Human iNKT cells can be divided into 2 major subsets depending on CD4 expression: CD4 (+) iNKT preferentially produce T-helper (Th)0/Th2 cytokines, whereas CD4(-) iNKT cells produce Th1 cytokines after antigenic activation. Cytokines produced by iNKT may have immunomodulatory roles in various physiopathologic contexts, but their mode of regulation by iNKT cells remains ill-defined. Using blocking reagents neutralizing CD4 binding, experimental systems where MHC class II molecules are absent and recombinant alpha-GalCer/CD1d complexes, we show that CD4 potentiates human iNKT cell activation by engaging CD1d molecules. These results indicate that the CD4 coreceptors may contribute to the fine tuning of iNKT cells reactivity.
authors.affiliation: Institute Nationale Scientifique et Recherche Medicale, Nantes, France.
authors.forename: Aurelie
authors.initials: A
authors.lastname: Thedrez
authors.forename: Claudia
authors.initials: C
authors.lastname: de Lalla
authors.forename: Sophie
authors.initials: S
authors.lastname: Allain
authors.forename: Luca
authors.initials: L
authors.lastname: Zaccagnino
authors.forename: Stephane
authors.initials: S
authors.lastname: Sidobre
authors.forename: Claudio
authors.initials: C
authors.lastname: Garavaglia
authors.forename: Giovanna
authors.initials: G
authors.lastname: Borsellino
authors.forename: Paolo
authors.initials: P
authors.lastname: Dellabona
authors.forename: Marc
authors.initials: M
authors.lastname: Bonneville
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Scotet
authors.forename: Giulia
authors.initials: G
authors.lastname: Casorati
mesh_terms: D018949:Antigens, CD1 / Q000276:immunology / Q000378:metabolism*; D055610:Antigens, CD1d; D015704:CD4 Antigens / Q000276:immunology / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D005699:Galactosylceramides / Q000276:immunology; D006649:Histocompatibility Antigens; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology
chemical_list: D018949:Antigens, CD1; D055610:Antigens, CD1d; C526877:CD1D protein, human; D015704:CD4 Antigens; D005699:Galactosylceramides; D006649:Histocompatibility Antigens; C493154:alpha-galactosylceramide