Minimal conformational plasticity enables TCR cross-reactivity to different MHC class II heterodimers
نویسندگان
چکیده
Successful immunity requires that a limited pool of αβ T-cell receptors (TCRs) provide cover for a vast number of potential foreign peptide antigens presented by 'self' major histocompatibility complex (pMHC) molecules. Structures of unligated and ligated MHC class-I-restricted TCRs with different ligands, supplemented with biophysical analyses, have revealed a number of important mechanisms that govern TCR mediated antigen recognition. HA1.7 TCR binding to the influenza hemagglutinin antigen (HA(306-318)) presented by HLA-DR1 or HLA-DR4 represents an ideal system for interrogating pMHC-II antigen recognition. Accordingly, we solved the structure of the unligated HA1.7 TCR and compared it to both complex structures. Despite a relatively rigid binding mode, HA1.7 T-cells could tolerate mutations in key contact residues within the peptide epitope. Thermodynamic analysis revealed that limited plasticity and extreme favorable entropy underpinned the ability of the HA1.7 T-cell clone to cross-react with HA(306-318) presented by multiple MHC-II alleles.
منابع مشابه
A structural voyage toward an understanding of the MHC-I-restricted immune response: lessons learned and much to be learned.
T cells that express clonally distributed αβ T-cell receptors (TCRs) corecognize antigenic peptides (p) bound to major histocompatibility complex class I (MHC-I) and class II molecules (MHC-II). Extensive human leukocyte antigen (HLA) polymorphism enables HLA molecules from different haplotypes to capture an array of self- and microbe-derived peptide antigens that is fundamental to adaptive imm...
متن کاملStructure of a Complex of the Human T Cell Receptor (TCR) HA1.7, Influenza Hemagglutinin Peptide, and Major Histocompatibility Complex Class II Molecule, HLA-DR4 (DRA * 0101 and DRB1 * 0401): Insight into TCR Cross-Restriction and Alloreactivity
The T cell receptor (TCR) HA1.7 specific for the hemagglutinin (HA) antigen peptide from influenza A virus is HLA-DR1 restricted but cross-reactive for the HA peptide presented by the allo-major histocompatibility complex (MHC) class II molecule HLA-DR4. We report here the structure of the HA1.7/DR4/HA complex, determined by X-ray crystallography at a resolution of 2.4 Å. The overall structure ...
متن کاملStructure of a Complex of the Human α/β T Cell Receptor (TCR) HA1.7, Influenza Hemagglutinin Peptide, and Major Histocompatibility Complex Class II Molecule, HLA-DR4 (DRA*0101 and DRB1*0401)
The alpha/beta T cell receptor (TCR) HA1.7 specific for the hemagglutinin (HA) antigen peptide from influenza A virus is HLA-DR1 restricted but cross-reactive for the HA peptide presented by the allo-major histocompatibility complex (MHC) class II molecule HLA-DR4. We report here the structure of the HA1.7/DR4/HA complex, determined by X-ray crystallography at a resolution of 2.4 A. The overall...
متن کاملConformational changes and flexibility in T-cell receptor recognition of peptide–MHC complexes
A necessary feature of the immune system, TCR (T-cell receptor) cross-reactivity has been implicated in numerous autoimmune pathologies and is an underlying cause of transplant rejection. Early studies of the interactions of alphabeta TCRs (T-cell receptors) with their peptide-MHC ligands suggested that conformational plasticity in the TCR CDR (complementarity determining region) loops is a dom...
متن کاملConformational melding permits a conserved binding geometry in TCR recognition of foreign and self molecular mimics.
Molecular mimicry between foreign and self Ags is a mechanism of TCR cross-reactivity and is thought to contribute to the development of autoimmunity. The αβ TCR A6 recognizes the foreign Ag Tax from the human T cell leukemia virus-1 when presented by the class I MHC HLA-A2. In a possible link with the autoimmune disease human T cell leukemia virus-1-associated myelopathy/tropical spastic parap...
متن کامل