The four members of the HLA-DR11 family of class II molecules vary only by three or fewer amino acids via dimorphisms among DRβ-chain residues 67, 71, and 86. However, they differ markedly in their abilities to induce proliferation of DR(α,β1*1101)-restricted, peptide-specific T cell clones. To dissect which DR11-variable residues, individually and in combination, mediate these functional differences, we used as APC transfectants expressing DR molecules with one of all possible permutations of DR11-variable sequences, including the four DR11 family members, and four additional DR11 variant mutants. The abilities of the wild-type or mutant molecules to present two distinct influenza peptide Ags, HA307-19 and HA128-45, to T cells was assessed in in vitro T cell proliferation assays. Of the naturally dimorphic DR11 positions, residue β 71 variation significantly influenced the ability of DR11 molecules to present both peptides to DR(α,β1*1101)- restricted T cells. Residue β 86 variation had relatively less influence than reported in several other DR and peptide systems. Residue β 67 variation usually appeared irrelevant to T cell proliferation, but in two mutants led to unexpected T cell proliferation independent of nominal peptide Ag. Peptide binding, assessed by flow cytometry, was not found to be altered by any mutations that disrupted DR(α,β1*1101)-like presentation. These data indicate that residue β 71 exerts a central role in influencing the functional differences among DR11 molecules, whereas the widely studied dimorphism of residue β 86 is not as generally influential in DR11 as in other alleles.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Immunology|
|State||Published - Dec 15 1994|
ASJC Scopus subject areas
- Immunology and Allergy