Immunology: Investigations on the cell type responsible for the endometrial secretion of complement component 3 (C3)

Abstract

It has been shown that rat and human endometria have the capacity to produce complement component 3 (C3). In rats, endometrial C3 is an oestrogen-dependent protein produced and secreted by glandular cells. The cell responsible for the synthesis and secretion of human endometrial C3 has not been clearly defined. Our study was aimed at answering this question. Samples of endometrium obtained from hysterectomies were either immunostained for C3 or digested with collagenase; then the stromal and glandular cells were separated and immunopurified (or not) with an antibody to CD45 coupled to magnetic beads to eliminate the endometrial lymphomyeloid cells. Cells were cultured for 2 weeks and C3 measured in the medium by an in-house radioimmunoassay. Glandular as well as stromal cells stained positively for C3 and released C3 in vitro. The release of C3 from both cell types could be inhibited by cycloheximide. Epithelial cells produced significantly more C3 than stromal cells, and endometrial C3 production was higher for both cell types when these were obtained from secretory as compared to proliferative endometria. Lymphomyeloid cells were possibly a source of C3 since after immunoadsorption of these cells, the remaining stromal or glandular cells produced significantly less C3. We conclude that endometrial stromal, glandular and lymphomyeloid cells all produce C3.

The ferroimmunomodulatory role of ectopic endometriotic stromal cells in ovarian endometriosis

“…Complement component C3 is a member of the complement system, thus associated with inflammation. Both glandular and stromal cells have been reported to secrete C3 in rats (24). Here, we have reported for the first time that immortalized ecESCs from OEM patients secrete C3 and PTX3.…”

Levels of complement components iC3b, C3c, C4, and SC5b-9 in peritoneal fluid and serum of infertile women with endometriosis

“…The most probable source of complement secretion is activated peritoneal macrophages (21). Ectopic endometrium also can produce C3 (20,22). The physiologic content of C3 in the endometrium appears to be regulated by hormones in a menstrual cycle-dependent manner; it is low in the follicular phase of the menstrual cycle and augmented in the luteal phase (23,24).…”

A co-operative interaction between Neisseria gonorrhoeae and complement receptor 3 mediates infection of primary cervical epithelial cells

“…, 2001). Production of some AP, but not classic pathway (CP), C′ components occurs within vaginal (Price and Boettcher, 1979) and endometrial epithelial cells (Barnum et al ., 1992; Vanderpuye et al ., 1992; Bischof et al ., 1994; Hasty et al ., 1994), and large amounts of C3 are produced by the uterus (Oglesby, 1998). Although full C′ activity has been demonstrated within cervical mucous, it is not clear if the presence of C′ in cervical mucous is the result of epithelial biosynthesis or transudation (Price and Boettcher, 1979; Vanderpuye et al ., 1992).…”