SYNTHESIS OF BETA(2) GLYCOPROTEIN-1 BY THE HUMAN PLACENTA

Autoantibodies to negatively charged phospholipids (aPL) can cause fet al loss, including recurrent miscarriage and stillbirth. The immunopat hogenic mechanism by which this occurs is unknown, but these antibodie s are known to bind phospholipid via a protein cofactor, beta(2) glyco protein 1. This protein is localized on placental syncytiotrophoblast and enables the binding of aPL from maternal blood. In this study, rev erse transcription and the polymerase chain reaction (RT-PCR) was used on mRNA isolated from normal human placental villous tissue and from human choriocarcinoma cell lines (jeg-3, BeWo and JAr) to demonstrate that placental cells themselves synthesize beta(2) glycoprotein 1 tran scripts. Protein production was confirmed by immunoblotting experiment s. Previous immunohistochemical studies were extended to demonstrate t hat beta(2) GP1 is localized to errtravillous cytotrophoblast in addit ion to syncytiotrophoblast. Production of beta(2) glycoprotein 1 by fe tal trophoblast indicates this protein is likely to have a physiologic al function in the placenta, and hence aPL may induce their pathologic al effect in pregnancy by inhibiting the function of placental beta(2) glycoprotein 1. (C) 1997 W. B. Saunders Company Ltd.