Effects of anti-swine zona serum on swine and murine in vitro fertilization.
No investigations have been reported concerning the action of anti-swine zona (anti-SZ) antibodies in a swine in vitro fertilization (IVF) system. We examined the effects of anti-SZ on homologous swine IVF and heterologous murine IVF. Swine IVF and sperm-zona binding were inhibited after treating swine ova with 2(2) and 2(1) dilutions of antiserum, producing fertility rates of 25.9% and 1.6% respectively, which are significantly lower than the control group fertility rate of about 70%. However, the murine ova could accept the capacitated homologous sperm, even after treatment with the antiserum-derived IgG, which had an antibody titer twice that of the starting antiserum. The antiserum-reacted swine ova exhibited a zona precipitate and a concentration-dependent resistance to pronase and required about 17 minutes to disappear after reacting with the starting antiserum, whereas the antiserum-reacted murine ova, which did not exhibit a zona precipitate, and the control ova disappeared within three minutes. These results indicate that antibody deposition on the zona greatly affects the degree of fertilization inhibition. The immunogens used were characterized zona constituent glycoproteins, and the antiserum raised against them was previously proven to be highly specific. Therefore, we believe that a basis has been established for analyzing the fertilization phenomena that take place at the zona using swine systems.