Immunological detection and characterization of an estrus-associated antigen in the goat oviduct

The present study was designed to investigate the possibility that the goat oviduct produces specific substance(s) similar to the oviductal glycoprotein (BOGP) of the bovine oviduct. Oviductal flushings obtained from goats at the follicular and luteal phases of the estrous cycle were examined by immunoblotting for the presence of material that cross-reacted with monoclonal antibodies (MAbs) specific for BOGP. The MAbs immunoreacted with a broad band with a molecular mass of protein of about 97 kDa in the flushings of goat oviducts after fractionation of proteins by electrophoresis under reducing conditions. The antigen was present in flushings obtained from the ampullar segments of oviducts from goats at the follicular stage, but this antigen could hardly be detected in the flushings from the ampulla at the luteal phase and or the flushings from the isthmus at either the follicular or the luteal phase. This antigen was not detected in uterine flushings, follicular fluid, or serum. An immunohistochemical study demonstrated that the MAbs reacted specifically with the epithelial cells of the goat oviduct. Intense labeling was observed in the ampullar and fimbrial epithelia of goat oviducts at the follicular phase, but the immunohistochemical reaction was very weak at the luteal phase. In the isthmus, the reaction was faint during both the follicular and the luteal phase. No specific immunohistochemical reactivity with the MAbs was observed with other tissues from the reproductive tract or with nonreproductive tissues. Immunofluorescent staining showed that the antigen was associated with the zona pellucida of goat ovarian eggs that had been incubated with ampullar flushings from goats at the follicular stage.(ABSTRACT TRUNCATED AT 250 WORDS)