ANALYSIS OF PEPTIDES ASSOCIATED WITH CLAS S-II MHC MOLECULES HLA-DR3 - IMPLICATION FOR PREDICTION OF PEPTIDES USEFUL FOR VACCINES

In order to characterize peptide binding motifs of MHC class II molecu les HLA-DR3, we have sequenced pool or single peptides eluted from the binding groove Anchor residue identified are in agreement with peptid e binding and sequencing studies reported by different groups. Four po sitions seem to be dominant (i, i + 3, i + 5, i + 8) while 2 secondary positions (i + 1, i + 2) could cooperate to facilitate binding. Accor ding to all the criteria define here and the literature, we propose an anchor motif specific for DR3, which has been tested on the sequence of an antigen from Schistosoma mansoni. Three out of 6 putative epitop es identified share common sequences with immunodominant regions deter mined in humans and by experimental immunizations in animal models. Ex tended to other alleles, this approach could be suitable to define pot entially immunodominant peptides useful for vaccines.