N. Kamada et al., Crucial amino acid residues of mouse CD1d for glycolipid ligand presentation to V(alpha)14NKT cells, INT IMMUNOL, 13(7), 2001, pp. 853-861
A novel lymphocyte, NKT cells bearing an invariant V(alpha)14 antigen recep
tor, specifically recognizes alpha -galactosylceramide (alpha -GalCer) excl
usively presented by mouse CD1d (mCD1d). However, the precise molecular int
eraction remains unclear. For the basis of functional analyses, a docking m
odel of alpha -GalCer with the crystal structure of mCD1d was constructed.
Possible residues involved in the alpha -GalCer-mCD1d interaction were foun
d to be Arg79, Glu83 and Asp80 for carbohydrate recognition, and Asp153 for
interaction with the amide group on the fatty acyl chain. The alpha -GaLCe
r-presenting ability of various transfectants expressing mutant mCD1d was c
ompletely abrogated it a single amino acid mutation was induced at position
s 79, 80, 83 or 153, suggesting that the polar amino acids above the F ' po
cket are crucial for alpha -GalCer presentation to activate V alpha 14 NKT
cells. The possibility that Glu83 is a contact site for the NKT cell recept
or is also discussed.