This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tse, P.-K. Articles by Yeung, W. S. B. Search for Related Content PubMed PubMed Citation Articles by Tse, P.-K. Articles by Yeung, W. S. B.

Preimplantation Embryos Cooperate with Oviductal Cells to Produce Embryotrophic Inactivated Complement-3b

Departments of Obstetrics and Gynaecology (P.-K.T., Y.-L.L., W.-N.C., K.-F.L., W.S.B.Y.) and Surgery (J.M.C.L.), The University of Hong Kong, Hong Kong Special Administrative Region, China

Address all correspondence and requests for reprints to: W. S. B. Yeung, Department of Obstetrics and Gynaecology, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Hong Kong, China. E-mail: wsbyeung{at}hkucc.hku.hk.

Human oviductal epithelial (OE) cells produce complement protein 3 (C3) and its derivatives, C3b and inactivated complement-3b (iC3b). Among them, iC3b is the most potent embryotrophic molecule. We studied the production of iC3b in the oviductal cell/embryo culture system. In the immune system, C3 convertase converts C3 into C3b, and the conversion of C3b to iC3b requires factor I (fI) and its cofactors, such as factor H or membrane cofactor protein. Human oviductal epithelium and OE cells expressed mRNA and protein of the components of C3 convertase, including C2, C4, factor B, and factor D. The OE cell-conditioned medium contained active C3 convertase activity that was suppressed by C3 convertase inhibitor, H17 in a dose and time-dependent manner. Although the oviductal epithelium and OE cells produced fI, the production of its cofactor, factor H required for the conversion of C3b to iC3b, was weak. Thus, OE cell-conditioned medium was inefficient in producing iC3b from exogenous C3b. On the contrary, mouse embryos facilitated such conversion to iC3b, which was taken up by the embryos, resulting in the formation of more blastocysts of larger size. The facilitatory activity was mediated by complement receptor 1-related gene/protein Y (Crry) with known membrane cofactor protein activity on the trophectoderm of the embryos as anti-Crry antibody inhibited the conversion and embryotrophic activity of C3b in the presence of fI. In conclusion, human oviduct possesses C3 convertase activity converting C3 to C3b, and Crry of the preimplantation embryos may be involved in the production of embryotrophic iC3b on the surface of the embryos.

This article has been cited by other articles:

				A. W.Y. Cheong, Y.-L. Lee, W.-M. Liu, W. S.B. Yeung, and K.-F. Lee Oviductal Microsomal Epoxide Hydrolase (EPHX1) Reduces Reactive Oxygen Species (ROS) Level and Enhances Preimplantation Mouse Embryo Development Biol Reprod, July 1, 2009; 81(1): 126 - 132. [Abstract] [Full Text] [PDF]