A SIMPLE ASSAY FOR DETECTION OF PEPTIDES PROMOTING THE ASSEMBLY OF HLA CLASS-I MOLECULES

Synthetic peptides derived from influenza virus and human immunodeficiency virus were tested for their ability to promote the assembly of HLA-A2 and HLA-B51 molecules in T2 cell lysates. Specific assembly was detected by an enzyme-linked immunosorbent assay. The most significant HLA-A2 assembly was obtained in the presence of peptides known to be targets for HLA-A2-restricted cytotoxic T lymphocytes (influenza matrix M.58-66 and HIV Pol 476-484). Three of a batch of Nef peptides corresponding to epitopic regions for cytotoxic T lymphocytes, caused significant assembly of HLA-A2 (Nef 83-91, 137-145 and 144-153), but only at high concentrations (100 mu M). As these peptides bound relatively weakly, it is unlikely that they are good candidates for HLA-A2-restricted CTL epitopes. Peptides matrix M.60-68, Nef 186-194, and Plasmodium falciparum sh.77-85 produced the most significant assembly of HLA-B51. These peptides have a dominant hydrophobic anchor residue (V, L. I) at position 9 that could occupy pocket ''F''. Our results also suggest that another hydrophobic residue (V, L) at position 3 or 4 may anchor to hydrophobic pocket ''D'' of HLA-B51. Proline at position 2 greatly increases HLA-B51 anchoring.