Synthesis, conformation, and immunogenicity of monosaccharide-centered multivalent HIV-1 gp41 peptides containing the sequence of DP178.

Several monosaccharide-centered multivalent HIV-1 gp41 peptides containing the sequence of DP178 were synthesized. Conformational studies showed that multivalent assembly enhanced the alpha-helical content of the peptide. Therefore, 2-, 3-, or 4-alpha-helix bundles of peptide DP178 could be obtained by assembling the peptide on a suitable bi-, tri-, or tetravalent template. Immunization studies indicated that while peptide DP178 alone was poorly immunogenic, the tetravalent peptide MVP-1 raised high titers of antibodies in mice that recognize not only peptide DP178 but also the native HIV-1 glycoprotein gp41, even in the absence of a carrier protein or adjuvant. The study suggests that carbohydrate-centered multivalent peptides provide not only a model for mimicking protein alpha-helix-bundle structure, but also an effective immunogen for raising high-titer antibodies against HIV-1 envelope glycoprotein gp41.