HLA-DP4 defines a new supertype of peptide-binding specificity.

2003 FEB 12 - (NewsRx.com & NewsRx.net) -- According to recent research from France, "Among HLA-DP specificities, HLA-DP4 specificity involves at least two molecules, HLA-DPA1*0103/DPBI*0401 (DP401) and HLA-DPA1*0103/DPB1*0402 (DP402), which differ from each other by only three residues. Together, they are present worldwide at an allelic frequency of 20-60% and are the most abundant human HLA II alleles. Strikingly, the peptide-binding specificities of these molecules have never been investigated."

"Hence, in this study, we report the peptide-binding motifs of both molecules," stated Florence A. Castelli and collaborators at the Commissariat a l'Energie Atomique-Saclay, SEDAC Therapeutics, and the Institut Cochin. "We first set up a binding assay specific for the immunopurified HLA-DP4 molecules. Using multiple sets of synthetic peptides, we successfully defined the amino acid preferences of the anchor residues. With these assays, we were also able to identify new peptide ligands from allergens and viral and tumor antigens. DP401 and DP402 exhibit very similar patterns of recognition in agreement with molecular modeling of the complexes. Pockets P1 and P6 accommodate the main anchor residues and interestingly contain only two polymorphic residues, beta-86 and ...