title: MR1 presentation of vitamin B-based metabolite ligands.
abstract: The major histocompatibility complex class I-related molecule MR1 can bind a novel class of antigens, namely a family of related small organic vitamin B metabolites. When bound to MR1 these metabolites are presented to a population of innate-like T cells, mucosal-associated invariant T (MAIT) cells that express a semi-invariant T cell receptor (TCR). Several non-activating and activating MR1-restricted ligands have been described, which are the degradation products of, or intermediates of, vitamin B9 (folic acid) or vitamin B2 (riboflavin), respectively. The MAIT-activating intermediates of the riboflavin synthesis pathway are unique to a wide range of microbes, and accordingly represent a molecular signature of microbial infection. Recently insights into the binding of these vitamin B metabolites to MR1, and subsequent recognition by the MAIT TCR, have been gleaned, illustrating a novel antigen presentation system.
authors.affiliation: Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: Hamish E  G
authors.initials: HE
authors.lastname: McWilliam
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Birkinshaw
authors.affiliation: Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria 3010, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville,Victoria 3010, Australia.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Villadangos
authors.affiliation: Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria 3010, Australia. Electronic address: jamesm1@unimelb.edu.au.
authors.forename: James
authors.initials: J
authors.lastname: McCluskey
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia; Institute of Infection and Immunity, Cardiff University, School of Medicine, Heath Park, Cardiff CF14 4XN, UK. Electronic address: jamie.rossjohn@monash.edu.
authors.forename: Jamie
authors.initials: J
authors.lastname: Rossjohn
mesh_terms: D000818:Animals; D015395:Histocompatibility Antigens Class I / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D018928:Immunity, Mucosal; D015778:Minor Histocompatibility Antigens; D008958:Models, Molecular; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D014815:Vitamins / Q000378:metabolism*
chemical_list: D015395:Histocompatibility Antigens Class I; C094840:MR1 protein, human; D015778:Minor Histocompatibility Antigens; D011948:Receptors, Antigen, T-Cell; D014815:Vitamins