A monoclonal antibody reacting with the zona pellucida of the oviductal egg but not with that of the ovarian egg of the golden hamster

A monoclonal antibody (mAb) designated AZPO-8 was produced by hybridizing a mouse myeloma with spleen cells from BALB/c mice immunized with materials obtained from the hamster oviduct. With an immunofluorescence test, AZPO-8 reacted with the zona pellucida (ZP) of ovulated eggs in the oviduct (ZP-OVI) but not with the zona pellucida of eggs in the ovary (ZP-OVA). Using indirect enzyme immunostaining, this mAb reacted with epithelial cells of the oviduct, the uterus (especially the cervical epithelium) and the gastric mucosa, but not with other hamster tissues examined. The reactivity of antigen-positive tissues was abrogated by pretreatment of the tissues with periodic acid. Western blotting analysis revealed that AZPO-8 reacted with substances of broad molecular weight range, and the strongest reactivity was detected at a molecular weight of approximately 200 000 in both cases when extract of ZP-OVI or the hamster oviduct was applied on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) gel. AZPO-8 showed strong hemagglutination activity only to group A human red blood cells. These results indicated that (1) ZP-OVI had an antigen that was not detected on ZP-OVA, (2) ZP-OVI and the oviduct shared the same antigenicity, and (3) the antigenic determinant reactive with the mAb might be carbohydrate in nature. A possible role of this antigen in fertilization was discussed.