IDENTIFICATION OF THE COMPLEMENT REGULATORY PROTEINS CD46, CD55, AND CD59 IN HUMAN FALLOPIAN-TUBE, ENDOMETRIUM, AND CERVICAL MUCOSA AND SECRETION

PROBLEM: Complement lytic activity has been demonstrated, and a potent ial for its activation is present in human cervical and tubal secretio ns and in the endometrium. This necessitates the presence of regulator y mechanisms for protection of the sperm and the implanting allogeneic conceptus in the female genital tract. Complement regulatory proteins demonstrated on sperm and in seminal fluid have been attributed such a role. It is however likely that additional protection is required fo r a successful conception and implantation to take place. This lead us to investigate the distribution of the complement regulatory factors in cervical mucus and mucosa, uterine endometrium, and fallopian tube. METHOD: Endometrium and cervical mucosa were obtained from patients u ndergoing hysterectomy for benign conditions, and specimens were selec ted from different stages of the menstrual cycle. Fallopian tubes were obtained from patients submitted for sterilization, while cervical mu cus was aspirated from volunteers undergoing gynecological examination . Immunohistochemistry was performed on all tissue samples, using mono clonal antibodies to membrane cofactor protein (MCP), decay accelerati ng factor (DAF), CD59 and complement receptor 1 (CR1). Western blot an alysis was performed on cervical mucus under nonreducing conditions. R ESULTS: MCP, DAF, and CD59 were found to be expressed in human endomet rium and fallopian tube. No variation in expression was detected throu ghout the menstrual cycle. CR1 was not expressed, Soluble forms of DAF and CD59 were found to be present in cervical mucus. CONCLUSION: The complement regulatory proteins MCP, DAF and CD59 are expressed through out the female genital tract, and may thus play an important role in p rotecting the traversing sperm and implanting blastocyst from compleme nt mediated damage.