Immunological characterization and immunocytochemical localization of an oviduct-specific glycoprotein in the human

The objective of the current study was to generate a polyclonal antibody toward a previously described 110- to 130-kilodalton (kDa) human oviductal glycoprotein and to use the antibody to detect the protein in tissue sections, tissue culture media, and oviductal flushings. The polyclonal antibody was generated in male rabbits against the 110- to 130-kDa glycoprotein partially purified from hydrosalpinx fluid. Segments of human oviducts were either cut into 2- to 3-mm pieces and cultured for 24 h, or fixed and embedded in Araldite for light and electron microscopic immunocytochemistry. The protein was only present in midcycle oviductal flushings and was most evident in culture medium samples obtained at midcycle when analyzed on Western blots. No cross-reactivity was observed with proteins in human serum or human endometrial and cervical explant culture media. Immunoperoxidase staining was observed in the apical granules of the secretory cells lining the oviductal lumen. No staining was noted in other parts of the oviduct or in sections of human endometrium and cervix. Indirect immunogold localization demonstrated specific clustering of gold particles over the apical granules of the secretory cells. In summary, a polyclonal antibody to a 110- to 130-kDa human oviductal glycoprotein was successfully generated. This protein is found in the secretory cells and is released into the oviductal lumen. The synthesis of this protein appears to require elevated levels of estrogen and may play a role in early reproductive events occurring within the oviduct.