Monoclonal antibodies specific for an oviductal component associated with the hamster zona pellucida

Five monoclonal antibodies (MAbs) were produced against oviductal zona pellucida (ZP) of the hamster. They were purified from ascitic fluid by high pressure liquid chromatography (HPLC) on hydroxylapatite (HPHT) and anion exchange columns. All five MAbs reacted selectively with oviductal ZP and oviductal secretions, no binding was observed to intra-ovarian ZP. A study of the tissue specificity, as evaluated by indirect immunofluorescence, revealed binding of all of these Abs only to the oviduct and, to a lesser extent, to the uterus. A cytosolic fraction from hamster oviduct was subjected to SDS-PAGE under reducing conditions and electro-transfer to a nitrocellulose membrane; immuno-enzymatic staining showed a reaction with a polydispersed oviductal component of high molecular weight (approx. 200,000). The native antigen has a molecular weight higher than 400,000 as determined by molecular sieve chromatography. These results suggest that an oviductal antigen is added to the hamster ZP during its transit through the oviduct. This antigen, called oviductin, is a heavily glycosylated protein of high molecular weight.