The Structure of H-2Kb and Kbm8 Complexed to a Herpes Simplex Virus Determinant: Evidence for a Conformational Switch That Governs T Cell Repertoire Selection and Viral Resistance Academic Article uri icon

abstract

  • Polymorphism within the MHC not only affects peptide specificity but also has a critical influence on the T cell repertoire; for example, the CD8 T cell response toward an immunodominant HSV glycoprotein B peptide is more diverse and of higher avidity in H-2(bm8) compared with H-2(b) mice. We have examined the basis for the selection of these distinct antiviral T cell repertoires by comparing the high-resolution structures of K(b) and K(bm8), in complex with cognate peptide Ag. Although K(b) and K(bm8) differ by four residues within the Ag-binding cleft, the most striking difference in the two structures was the disparate conformation adopted by the shared residue, Arg(62). The altered dynamics of Arg(62), coupled with a small rigid-body movement in the alpha(1) helix encompassing this residue, correlated with biased Valpha usage in the B6 mice. Moreover, an analysis of all known TCR/MHC complexes reveals that Arg(62) invariably interacts with the TCR CDR1alpha loop. Accordingly, Arg(62) appears to function as a conformational switch that may govern T cell selection and protective immunity.

authors

  • Webb, Andrew I
  • Borg, Natalie A
  • Dunstone, Michelle A
  • Kjer-Nielsen, Lars
  • Beddoe, Travis
  • McCluskey, James
  • Carbone, Francis R
  • Bottomley, Stephen P
  • Aguilar, Marie-Isabel
  • Purcell, Anthony W
  • Rossjohn, Jamie

publication date

  • July 1, 2004