Localization of a carbohydrate antigen associated with growing oocytes and ovarian surface epithelium

We used a monoclonal antibody (PS1) to a carbohydrate antigen to study the development of the oocyte and follicle during early stages of differentiation in several mammalian species. This antigen has been shown to localize within the cytoplasm of oocytes in primordial follicles as well as in growing oocytes. It is also localized within distinct layers of the zona pellucida (ZP) of developing follicles. Although this antibody was made against a specific ZP glycoprotein, the antigen also appears to be abundant in cells of the ovarian surface epithelium (OSE). The localization of this carbohydrate moiety has been observed in ovaries of rabbits of different ages as well as in the ovarian surface epithelium of other mammalian species including cat, cynomolgus monkey, baboon, and human. These studies demonstrate that there is an abundant carbohydrate antigenic determinant which is associated with both the mammalian oocyte and the ovarian surface epithelium but which is not apparent in other ovarian cell types or in non-ovarian secretory epithelium. This antibody probe should provide a valuable tool for studying the development and differentiation of the ovary, since this antigen is associated with two highly differentiated but distinct cell types.