Monoclonal antibodies as probes of the distribution of ZP-2, the major sulfated glycoprotein of the murine zona pellucida.

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Abstract
Three sulfated glycoproteins (ZP-1, ZP-2, and ZP-3) make up the zona pellucida, an extracellular glycocalyx that surrounds mouse oocytes. Five monoclonal antibodies specific to the zona were produced. All 5 immunoprecipitated ZP-2, and in addition, 2 of the antibodies immunoprecipitated ZP-3, suggesting the presence of either a common antigenic site or one made up in part by each of the 2 glycoproteins. The monoclonal antibodies bound to .apprx. 1.3 .times. 108 binding sites per ovulated mouse egg which represents 2% of the total number of ZP-2 molecules present in the zona. ZP-2 appeared to be present throughout the zona and indirect immunofluorescence revealed a fibrous pattern with no evidence of localization. This pattern of distribution, which was identical for all 5 monoclones, remained constant after fertilization at the 2-cell embryo stage. Laser photobleaching demonstrated that ZP-2 is stably integrated in the extracellular matrix of the zona pellucida. No mouse tissue other than the ovary contained ZP-2 and ZP-2 is antigenically distinct from other previously described extracellular matrix proteins.