Control of the humoral immune system within the rabbit oviduct.

Within the oviduct the maternal humoral immune system can react with the sperm on their way to fertilize the ovum and with preimplantation embryos which express paternal surface antigens. The embryo or sperm is destroyed by antibodies plus complement; thus control of the humoral immune system in the oviduct is advantageous. This paper confirms the absence of whole complement in the oviduct as determined by both in vivo and in vitro hemolytic assays. Further, it is established that there exists within oviductal fluid a concentration-dependent inhibition of complement activity. This inhibitor is heat labile and nondialyzable. Utilizing purification by Sephadex G-200 and ion-exchange chromatography, the complement inhibition was attributed to a family of sulfated glycoproteins secreted by the oviductal epithelium.