Immunohistochemical localization of C9 neoantigen and the terminal complement inhibitory protein CD59 in human endometrium.
OBJECTIVE
Human endometrium expresses complement components, receptors, and regulatory proteins, many of which appear to be expressed in a hormone-dependent manner. Whether terminal complement components are also present in the endometrium is unknown. CD59, a broadly expressed protein that blocks association of C9 with C8 in the membrane attack complex, is localized in reproductive tissue to human spermatozoa, seminal plasma, amniotic fluid, and placenta. The present study examines human endometrium for the presence of CD59 and terminal complement proteins.


METHODS
Endometrial biopsies were obtained from six normal women from various phases of the menstrual cycle and analyzed by immunohistochemistry, using MEM-43 anti-human CD59 and anti-human SC5b-9 murine monoclonal antibodies and the immunoperoxidase technique.


RESULTS
Both CD59 protein and SC5b-9 (C9 neoantigen) were demonstrated to be present in endometrial glandular epithelium throughout the menstrual cycle. No specific staining was demonstrated in the stromal compartment.


CONCLUSIONS
CD59 protein and terminal complement proteins are expressed in glandular epithelial cells of normal human endometrium, in both proliferative and luteal phases, suggesting that expression is not hormonally dependent. These analyses further support the presence of a functionally active complement system in normal human endometrium.
Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
W D
WD
Ratnoff
W W
WW
Brockman
L A
LA
Hasty
D000941:Antigens / Q000737:chemistry*; D018957:CD59 Antigens / Q000737:chemistry* / Q000494:pharmacology; D003186:Complement C9 / Q000737:chemistry*; D003169:Complement Inactivator Proteins / Q000737:chemistry* / Q000494:pharmacology; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000187:drug effects*; D004717:Endometrium / Q000737:chemistry* / Q000276:immunology; D005260:Female; D006023:Glycoproteins / Q000187:drug effects*; D006801:Humans; D007150:Immunohistochemistry
D000941:Antigens; D018957:CD59 Antigens; D003186:Complement C9; D003169:Complement Inactivator Proteins; D015938:Complement Membrane Attack Complex; D006023:Glycoproteins; C047610:SC5b-9 protein complex; D003165:Complement System Proteins