Article

Structure of a human autoimmune TCR bound to a myelin basic protein self-peptide and a multiple sclerosis-associated MHC class II molecule.

Center for Advanced Research in Biotechnology, WM Keck Laboratory for Structural Biology, University of Maryland Biotechnology Institute, Rockville, MD 20850, USA.
The EMBO Journal (Impact Factor: 9.82). 10/2005; 24(17):2968-79. DOI: 10.1038/sj.emboj.7600771
Source: PubMed

ABSTRACT Multiple sclerosis is mediated by T-cell responses to central nervous system antigens such as myelin basic protein (MBP). To investigate self-peptide/major histocompatibility complex (MHC) recognition and T-cell receptor (TCR) degeneracy, we determined the crystal structure, at 2.8 A resolution, of an autoimmune TCR (3A6) bound to an MBP self-peptide and the multiple sclerosis-associated MHC class II molecule, human leukocyte antigen (HLA)-DR2a. The complex reveals that 3A6 primarily recognizes the N-terminal portion of MBP, in contrast with antimicrobial and alloreactive TCRs, which focus on the peptide center. Moreover, this binding mode, which may be frequent among autoimmune TCRs, is compatible with a wide range of orientation angles of TCR to peptide/MHC. The interface is characterized by a scarcity of hydrogen bonds between TCR and peptide, and TCR-induced conformational changes in MBP/HLA-DR2a, which likely explain the low observed affinity. Degeneracy of 3A6, manifested by recognition of superagonist peptides bearing substitutions at nearly all TCR-contacting positions, results from the few specific interactions between 3A6 and MBP, allowing optimization of interface complementarity through variations in the peptide.

1 Bookmark
 · 
58 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Self-reactive CD4 T cells are thought to have a central role in the pathogenesis of many chronic inflammatory human diseases. Microbial peptides can activate self-reactive T cells, but the structural basis for such crossreactivity is not well understood. The Hy.1B11 T cell receptor (TCR) originates from a patient with multiple sclerosis and recognizes the self-antigen myelin basic protein. Here we report the structural mechanism of TCR crossreactivity with two distinct peptides from human pathogens. The structures show that a single TCR residue (CDR3α F95) makes the majority of contacts with the self-peptide and both microbial peptides (66.7-80.6%) due to a highly tilted TCR-binding topology on the peptide-MHC surface. Further, a neighbouring residue located on the same TCR loop (CDR3α E98) forms an energetically critical interaction with the MHC molecule. These data show how binding by a self-reactive TCR favors crossreactivity between self and microbial antigens.
    Nature Communications 10/2013; 4:2623. · 10.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Topological and stereo-electron characteristics are essential in major histocompability class II-peptide-T-cell receptor (MHC-p-TCR) complex formation for inducing an appropriate immune response. Modified high activity binding peptides (mHABPs) were synthesised for complete full protection antimalarial vaccine development producing a large panel of individually fully protection-inducing protein structures (FPIPS) and very high long-lasting antibody-inducing (VHLLAI) mHABPs. Most of those which did not interfere, compete, inhibit or suppress their individual VHLLAI or FPIPS activity contained or displayed a polyproline II-like (PPIIL) structure when mixed. Here we show that amino acid side-chains located in peptide binding region (PBR) positions p3 and p7 displayed specific electron charges and side-chain gauche(+) orientation for interacting with the TCR. Based on the above, and previously described physicochemical principles, non-interfering, long-lasting, full protection-inducing, multi-epitope, multistage, minimal subunit-based chemically synthesised mHABP mixtures can be designed for developing vaccines against diseases scourging humankind, malaria being one of them.
    Vaccine 02/2014; · 3.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Chronic beryllium disease (CBD) is a granulomatous lung disorder caused by a hypersensitivity to beryllium and characterized by the accumulation of beryllium-specific CD4(+) T cells in the lung. Genetic susceptibility to beryllium-induced disease is strongly associated with HLA-DP alleles possessing a glutamic acid at the 69th position of the β-chain (βGlu69). The structure of HLA-DP2, the most prevalent βGlu69-containing molecule, revealed a unique solvent-exposed acidic pocket that includes βGlu69 and represents the putative beryllium-binding site. The delineation of mimotopes and endogenous self-peptides that complete the αβTCR ligand for beryllium-specific CD4(+) T cells suggests a unique role of these peptides in metal ion coordination and the generation of altered self-peptides, blurring the distinction between hypersensitivity and autoimmunity.
    Current opinion in immunology 08/2013; · 10.88 Impact Factor

Full-text

Download
0 Downloads
Available from