An important role played by trophoblast cells at the feto-maternal interface is to exert immunomodulatory functions, including recognition of bacterial and viral agents and recruitment of leucocytes to eradicate pathogens. In this study we present data showing that the trophoblast cell line HTR8/SVneo and freshly isolated human first trimester trophoblast cells (CTBs) synthesize complement molecules C4, C3 and the late complement components, as assessed by ELISA and RT-PCR. Both cell types secrete C4 and C3, and HTR8/SVneo trophoblast cells secrete C6 in a measurable amount. The expression of C4 by HTR8/SVneo trophoblast cells and of C3 and C4 by CTBs was up-regulated by IFNgamma, while IL-1alpha and TNFalpha had no effect on the expression of complement components. In conclusion, we show that trophoblast cells produce complement components, and that synthesis of these proteins may be regulated by the pro-inflammatory cytokine IFNgamma. Complement synthesis by trophoblast cells potentially contributes to placental immune defence from pathogen infection.
