Microbiology & Immunology - Research Publications

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    CD1d-lipid antigen recognition by the γδ TCR
    Uldrich, AP ; Le Nours, J ; Pellicci, DG ; Gherardin, NA ; McPherson, KG ; Lim, RT ; Patel, O ; Beddoe, T ; Gras, S ; Rossjohn, J ; Godfrey, DI (NATURE PUBLISHING GROUP, 2013-11)
    The T cell repertoire comprises αβ and γδ T cell lineages. Although it is established how αβ T cell antigen receptors (TCRs) interact with antigen presented by antigen-presenting molecules, this is unknown for γδ TCRs. We describe a population of human Vδ1(+) γδ T cells that exhibit autoreactivity to CD1d and provide a molecular basis for how a γδ TCR binds CD1d-α-galactosylceramide (α-GalCer). The γδ TCR docked orthogonally, over the A' pocket of CD1d, in which the Vδ1-chain, and in particular the germ line-encoded CDR1δ loop, dominated interactions with CD1d. The TCR γ-chain sat peripherally to the interface, with the CDR3γ loop representing the principal determinant for α-GalCer specificity. Accordingly, we provide insight into how a γδ TCR binds specifically to a lipid-loaded antigen-presenting molecule.
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    Antigen-loaded MR1 tetramers define T cell receptor heterogeneity in mucosal-associated invariant T cells
    Reantragoon, Rangsima ; Corbett, Alexandra J. ; Sakala, Isaac G. ; Gherardin, Nicholas A. ; Furness, John B. ; CHEN, ZHENJUN ; Eckle, Sidonia B.G. ; Uldrich, Adam P. ; Birkinshaw, Richard W. ; Patel, Onisha ; KOSTENKO, LYUDMILA ; MEEHAN, BRONWYN ; KEDZIERSKA, KATHERINE ; Liu, Ligong ; Fairlie, David P. ; Hansen, Ted H. ; GODFREY, DALE I. ; ROSSJOHN, JAMIE ; MCCLUSKEY, JAMES ; KJER-NIELSEN, LARS (Rockefeller University Press, 2013)
    Mucosal-associated invariant T cells (MAIT cells) express a semi-invariant T cell receptor (TCR) alpha-chain, TRAV1-2-TRAJ33, and are activated by vitamin B metabolites bound by the major histocompatibility complex (MHC)-related class I-like molecule, MR1. Understanding MAIT cell biology has been restrained by the lack of reagents to specifically identify and characterize these cells. Furthermore, the use of surrogate markers may misrepresent the MAIT cell population. We show that modified human MR1 tetramers loaded with the potent MAIT cell ligand, reduced 6-hydroxymethyl-8-D-ribityllumazine (rRL-6-CH2OH), specifically detect all human MAIT cells. Tetramer(+) MAIT subsets were predominantly CD8(+) or CD4(-)CD8(-), although a small subset of CD4(+) MAIT cells was also detected. Notably, most human CD8(+) MAIT cells were CD8 alpha(+)CD8 beta(-/lo), implying predominant expression of CD8 alpha alpha homodimers. Tetramer-sorted MAIT cells displayed a T(H)1 cytokine phenotype upon antigen-specific activation. Similarly, mouse MR1-rRL-6-CH2OH tetramers detected CD4(+), CD4(-)CD8(-) and CD8(+) MAIT cells in V. 19 transgenic mice. Both human and mouse MAIT cells expressed a broad TCR-beta repertoire, and although the majority of human MAIT cells expressed TRAV1-2-TRAJ33, some expressed TRAJ12 or TRAJ20 genes in conjunction with TRAV1-2. Accordingly, MR1 tetramers allow precise phenotypic characterization of human and mouse MAIT cells and revealed unanticipated TCR heterogeneity in this population.