Polyclonal antibodies to a 32-KDA deglycosylated polypeptide from porcine zonae pellucidae will prevent human gamete interaction in vitro

The major deglycosylated polypeptides of the porcine zona pellucida (ZP), with molecular masses of 66, 52, 36, and 32 kDa, were purified to homogenity with one-dimensional sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS/PAGE). Immunofluorescence studies demonstrated that antibodies to the DGZP fraction, and the 66- and 32-kDa polypeptides, bound predominantly to the outer ZP; however, only the first two of these antisera formed an immunoprecipitate around the outer human ZP. In immunoblotting experiments using polyclonal antisera raised to these molecules all four polypeptides exhibited cross-reactivity with each other and their parental glycoprotein families (ZP 1–4). In addition, the antisera were tested in an in vitro human gamete bioassay to determine their contraceptive potential; antibodies to the 32-kDa deglycosylated polypeptide inhibited human gamete interaction to the greatest extent, 5.3% (± 1.2%), relative to a control value of 100%.