Phage-displayed peptides mimicking the discontinuous neutralization sites of Puumala hantavirus envelope glycoproteins

We selected peptide ligands mimicking the surface structure of discontinuou s binding sites of Puumala hantavirus-neutralizing monoclonal antibodies fr om a random 18-amino acid peptide library containing a disulfide bridge in a fixed position and displayed on a filamentous phage. The varying of selec tion conditions, either by shortening of the association time or by competi tive elution with antigen, was crucial for the selection of peptide inserts that could be aligned with the primary sequences of the envelope glycoprot eins G1 and G2. Correspondingly, when the envelope glycoprotein sequences w ere synthesized as overlapping peptides as spots on membrane, the same site in primary structure was found as with phage display, which corroborates t he use of the two methods in mapping of conformational epitopes. Also, epit opes reactive with early-phase sera from Puumala virus infection were defin ed with the pepspot assay in the amino-terminal region of G1. Similarities of the selected phage clones to a monoclonal antibody-escape mutant site an d to a linear early-phase epitope were found. (C) 1999 Academic Press.