Chemical synthesis of a decapeptide eliciting characteristics of a human spermatozoal antigen.

Antigenic spermatozoal polypeptides were purified by immunoaffinity chromatography, using immobilized immunoglobulin G from a sterile woman. One of these peptides showed Asp as N-terminal amino acid and had a sequence of Asp-Pro-Trp-Trp-Cys-Phe-Asp-Lys-Phe-Glu. Following synthesis, the synthetic peptide was tested in immunoinhibition test for its ability to react with anti-spermatozoal antibodies. In a solid-phase immunoassay significant inhibition of a rabbit anti-human spermatozoal antiserum was evident (Student 't' test p less than 0.05). The peptide also reacted with the naturally occurring agglutinating antispermatozoal antibodies in sera of sterile patients in 7 out of 9 cases (p less than 0.05). These results could open the way for the development of synthetic spermatozoal antigen preparations for an immunological regulation of fertility.