title: Self/non-self discrimination by human gammadelta T cells: simple solutions for a complex issue?
abstract: Although gammadelta T cells express clonally distributed T-cell receptors (TCRs), a hallmark of adaptive immunity, they are classically considered as innate-like effectors, owing to the high frequency of preactivated gammadelta T cells, with restricted antigen recognition repertoire in particular tissue locations. Actually, such features are shared only by a fraction of gammadelta T-cell subsets located in the skin and reproductive organ mucosa in rodents or in peripheral blood in humans. By contrast, other gammadelta subsets, e.g. those found in rodent and human spleen, show diverse antigenic reactivity patterns and mixed naive/memory phenotypes. Thus, gammadelta T cells are made of both 'primitive' subsets endowed with innate-like properties and 'evolved' subsets able to mount anamnestic responses like conventional major histocompatibility complex-restricted alphabeta T cells. In this article, we show that human gammadelta T cells, although heterogeneous, do share recurrent innate features that distinguish them from mainstream alphabeta T cells. In particular, most of them are activated on TCR- or natural killer receptor-mediated recognition of a restricted set of conserved yet poorly defined endogenous stress determinants. This rather simple recognition mechanism allows human gammadelta T cells to discriminate healthy cells from altered cells and to exert a variety of immunostimulatory or regulatory functions. The recent availability of synthetic gammadelta T-cell agonists mimicking these natural stress-induced ligands have fostered development of immunotherapeutic strategies, with broad indications against infectious and tumor diseases, which are briefly reviewed here.
authors.affiliation: INSERM U601, Département de Recherche en Cancérologie, Institut de Biologie/CHU, Nantes, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Thedrez
authors.forename: Caroline
authors.initials: C
authors.lastname: Sabourin
authors.forename: Julie
authors.initials: J
authors.lastname: Gertner
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Devilder
authors.forename: Sophie
authors.initials: S
authors.lastname: Allain-Maillet
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Fournié
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Scotet
authors.forename: Marc
authors.initials: M
authors.lastname: Bonneville
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000276:immunology; D015551:Autoimmunity; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D018448:Models, Immunological; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D017634:Self Tolerance / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*
chemical_list: D001324:Autoantigens; D016692:Receptors, Antigen, T-Cell, gamma-delta