Peptide-binding assays and HLA II transgenic Aβ° mice are consistent and complementary tools for identifying HLA II-restricted peptides

The identification of MHC class II-restricted peptides has become a priority for the development of peptide-based prophylactic and therapeutic vaccines. The aim of this study was to assess the correlations between peptide-binding assays on purified HLA II molecules and immunization of human HLA II transgenic mice deficient in murine class II molecules (Aβ°). We used as models two MHC class II-restricted peptides, one derived from the HIV Nef regulatory protein (Nef 56–68) and the other from the Schistosoma mansoni 28-kDa glutathione-S-transferase (Sm28GST 190–211). High correlations were found between the two approaches, which showed that the Nef 56–68 and Sm28GST 190–211 peptides may represent promiscuous ligands for HLA-DQ and for HLA-DR molecules, respectively. We suggest a rational method based on the combination of peptide-binding assays and HLA II transgenic mice experiments as consistent and complementary tools for selecting T helper epitopes.