Efficacy of a Recombinant Chimeric Anti‐hCG Antibody to Prevent Human Cytotrophoblasts Fusion and Block Progesterone Synthesis

Problem: A recombinant chimeric antibody against hCG (cPIPP) has been engineered and expressed at high yield in plants. The purpose of this work was to enquire whether this antibody is competent to neutralize the bioactivity of hCG on human trophoblasts. Methods:  Cytotrophoblast cells, isolated from term placentae were maintained in culture for 3 days in presence or absence of humanized chimeric anti-hCG antibodies. Progesterone secreted was quantitated by ELISA. Fusion and cyto-architecture of the cells was studied by light and electron microscopy. Modulation of E-cadherin was investigated using RT-PCR and immunocytochemistry. Results:  Recombinant chimeric anti-hCG antibody blocked the synthesis of progesterone by trophoblasts. No fusion of cytotrophoblasts to form syncytium took place. E-cadherin, a vital cell adhesion molecule involved in cell-to-cell interaction did not show differentiation related decline in its expression in presence of the antibody. Conclusion:  Recombinant chimeric anti-hCG antibody (cPIPP) was effective to neutralize hCG induced bioactivities in the human derived trophoblast cells.