A structural basis for selection and cross-species reactivity of the semi-invariant NKT cell receptor in CD1d/glycolipid recognition Academic Article uri icon

abstract

  • Little is known regarding the basis for selection of the semi-invariant alphabeta T cell receptor (TCR) expressed by natural killer T (NKT) cells or how this mediates recognition of CD1d-glycolipid complexes. We have determined the structures of two human NKT TCRs that differ in their CDR3beta composition and length. Both TCRs contain a conserved, positively charged pocket at the ligand interface that is lined by residues from the invariant TCR alpha- and semi-invariant beta-chains. The cavity is centrally located and ideally suited to interact with the exposed glycosyl head group of glycolipid antigens. Sequences common to mouse and human invariant NKT TCRs reveal a contiguous conserved "hot spot" that provides a basis for the reactivity of NKT cells across species. Structural and functional data suggest that the CDR3beta loop provides a plasticity mechanism that accommodates recognition of a variety of glycolipid antigens presented by CD1d. We propose a model of NKT TCR-CD1d-glycolipid interaction in which the invariant CDR3alpha loop is predicted to play a major role in determining the inherent bias toward CD1d. The findings define a structural basis for the selection of the semi-invariant alphabeta TCR and the unique antigen specificity of NKT cells.

authors

  • Kjer-Nielsen, Lars
  • Borg, Natalie A
  • Pellicci, Daniel G
  • Beddoe, Travis
  • Kostenko, Lyudmila
  • Clements, Craig S
  • Williamson, Nicholas A
  • Smyth, Mark J
  • Besra, Gurdyal S
  • Reid, Hugh H
  • Bharadwaj, Mandvi
  • Godfrey, Dale I
  • Rossjohn, Jamie
  • McCluskey, James

publication date

  • March 20, 2006

has subject area