gammadelta T cells link innate and adaptive immune responses.
While most T cells use a CD3-associated alpha/beta T cell receptor as antigen recognition structure, a second population of T cells expresses the alternative gamma/delta T cell receptor. gamma/delta T cells are a minor population in the peripheral blood but constitute a major population among intestinal intraepithelial lymphocytes. Most gamma/delta T cells recognize ligands which are fundamentally different from the short peptides that are seen by alpha/beta T cells in the context of MHC class I or class II molecules. Thus, human Vdelta2 T cells recognize small bacterial phosphoantigens, alkylamines and synthetic aminobisphosphonates, whereas Vdelta1 T cells recognize stress-inducible MHC-related molecules MICA/B as well as several other ligands. At the functional level, gamma/delta T cells rapidly produce a variety of cytokines and usually exert potent cytotoxic activity, also towards many tumor cells. In this article, we discuss the role of gamma/delta T cells as a bridge between the innate and the adaptive immune system, based on the interpretation that gamma/delta T cells use their T cell receptor as a pattern recognition receptor. Our increasing understanding of the ligand recognition and activation mechanisms of gamma/delta T cells also opens new perspectives for the development of gamma/delta T cell-based immunotherapies.
Holtmeier
Wolfgang
W
Medizinische Klinik I., Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany.
Kabelitz
Dieter
D
D000222:Adaptation, Physiological; D000941:Antigens; D018925:Chemokines / Q000378:metabolism; D004848:Epithelium / Q000276:immunology; D006090:Gram-Negative Bacteria / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate; D007239:Infections / Q000276:immunology; D007422:Intestines / Q000166:cytology / Q000276:immunology; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000276:immunology; D009369:Neoplasms / Q000276:immunology / Q000628:therapy; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D051193:Toll-Like Receptors
D000941:Antigens; D018925:Chemokines; D008562:Membrane Glycoproteins; D016692:Receptors, Antigen, T-Cell, gamma-delta; D011956:Receptors, Cell Surface; D051193:Toll-Like Receptors