Human complement regulator expression by the normal female reproductive tract.
BACKGROUND
The membrane-associated proteins that regulate human complement activation are ubiquitously expressed and function cooperatively to protect cells from autologous complement damage. For classical and alternative pathways, the primary regulators at the stage of C3 proteolysis and deposition are membrane cofactor protein (MCP; CD46) and decay-accelerating factor (DAF;CD55), whereas protectin or CD59 regulates terminal component assembly. There is increasing awareness in reproductive, tumor, and transplantation immunology of the conventional and non-complement roles of these proteins. The human reproductive system may serve as a model of the non-complement functions.


METHODS
We performed immunohistochemical analyses of multiple normal ovaries, fallopian tubes, cervices, and uterine corpi by using well-characterized monoclonal antibodies to provide a detailed, direct comparison of complement regulator expression.


RESULTS
Membrane cofactor protein was diffusely and strongly expressed on all epithelia and vascular endothelium and was the predominant regulator on oocytes. In contrast, decay-accelerating factor had variable expression in intensity and distribution on epithelia and was notably absent on certain epithelia and oocytes. It was the only regulator present on the connective tissue between muscle bundles in the myometrium and the cervix and was found on most stroma. CD59, although staining intensity varied, was present on virtually all epithelia, vascular tissue, and stroma.


CONCLUSIONS
Distinct reproducible patterns of complement regulator expression are found throughout the female reproductive tract. Differential expression on certain epithelia and oocytes may suggest non-complement activities. This comprehensive study should provide a basis for further characterization of pathological tissues and mechanisms of cellular localization.
Oglesby
T J
TJ
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Longwith
J E
JE
Huettner
P C
PC
D015703:Antigens, CD / Q000378:metabolism*; D001808:Blood Vessels / Q000378:metabolism; D018958:CD55 Antigens / Q000378:metabolism*; D018957:CD59 Antigens / Q000378:metabolism*; D003165:Complement System Proteins / Q000378:metabolism*; D003338:Corpus Luteum / Q000166:cytology / Q000378:metabolism; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D005260:Female; D005836:Genitalia, Female / Q000098:blood supply / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D006080:Ovarian Follicle / Q000378:metabolism; D012016:Reference Values; D017154:Stromal Cells / Q000378:metabolism
D015703:Antigens, CD; C497857:CD46 protein, human; D018958:CD55 Antigens; D018957:CD59 Antigens; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins; D003165:Complement System Proteins