Immunological comparison of antibodies to porcine zonae pellucidae in rats and rabbits.

Rats and rabbits immunized with porcine zonae pellucidae (ZP) develop antibodies to specific ZP proteins. The proteins recognized by rabbit and rat antibodies were identified using immunoblot procedures. For these studies, proteins were separated by high-resolution, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Proteins were transferred electrophoretically to nitrocellulose paper and antibody binding determined using 125I-labeled Staphylococcus aureus protein A (Staph A). The three major porcine ZP glycoprotein families were recognized by antibodies in the sera of both rabbits and rats. These antibodies were further characterized using Staph A binding and enzyme-linked (ELISA) immunoassays. Rabbits immunized with porcine ZP developed antibodies which recognized the porcine ZP as well as rat ZP antigens. Rats immunized with porcine ZP produced antibodies which recognized porcine ZP antigens but did not react with rat ZP antigens. While antibodies to porcine ZP, detected by Staph A binding and ELISA assays, correlated with infertility in rabbits [Wood et al. (1981) Biol. Reprod. 25:439], rats having these antibodies could have normal offspring. Continued fertility in rats following immunization with porcine ZP may be due to the failure to induce autoantibodies which recognized self ZP antigenic determinants.