Enhanced production of monoclonal antibodies against zona pellucida-free, unfertilized mouse oocytes by intrasplenic immunization.

Monoclonal antibodies were obtained by intrasplenic insertion of a total of 40-50 zona pellucida-free, unfertilized mouse oocytes into each mouse. The oocytes were prepared by a combined enzyme-mechanical method without impairing the fertility of the oocyte or inducing parthenogenesis. Of a total of 1063 hybrids obtained, 15 yielded supernatants with positive reactions to unfertilized oocytes. Tests for preimplantation stage specificity demonstrated that 9 of the supernatants detected antigen epitopes in unfertilized oocytes only. The other supernatants showed positive reaction patterns to various embryonal stages of the preimplantation period. Two supernatants recognized materials in the culture medium shedded by zona pellucida-free oocytes. Thus, by applying intrasplenic immunization, the production of antibodies against zona pellucida-free mouse oocytes is enhanced. The procedures described outline a rational way of selecting antibodies of interest for research in the mechanism of fertilization.