title: Role of the T cell receptor alpha chain in stabilizing TCR-superantigen-MHC class II complexes.
abstract: Superantigens (SAGs) activate T cells by simultaneously binding the Vbeta domain of the TCR and MHC class II molecules on antigen-presenting cells. The preferential expression of certain Valpha regions among SAG-reactive T cells has suggested that the TCR alpha chain may modulate the level of activation through an interaction with MHC. We demonstrate that the TCR alpha chain is required for maximum stabilization of the TCR-SAG-MHC complex and that the alpha chain increases the half-life of the complex to match those of TCR-peptide/MHC complexes. The site on the TCR alpha chain responsible for these effects is CDR2. Thus, the overall stability of the TCR-SAG-MHC complex is determined by the combination of three distinct interactions: TCR-SAG, SAG-MHC, and MHC-TCR.
authors.affiliation: Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville 20850, USA.
authors.forename: P S
authors.initials: PS
authors.lastname: Andersen
authors.forename: P M
authors.initials: PM
authors.lastname: Lavoie
authors.forename: R P
authors.initials: RP
authors.lastname: Sékaly
authors.forename: H
authors.initials: H
authors.lastname: Churchill
authors.forename: D M
authors.initials: DM
authors.lastname: Kranz
authors.forename: P M
authors.initials: PM
authors.lastname: Schlievert
authors.forename: K
authors.initials: K
authors.lastname: Karjalainen
authors.forename: R A
authors.initials: RA
authors.lastname: Mariuzza
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics / Q000276:immunology; D000818:Animals; D004768:Enterotoxins / Q000737:chemistry / Q000378:metabolism*; D015798:HLA-DR1 Antigen / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D018089:Superantigens / Q000737:chemistry / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D004768:Enterotoxins; D015798:HLA-DR1 Antigen; D046911:Macromolecular Substances; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018089:Superantigens; C031818:enterotoxin B, staphylococcal