Evidence for the expression of granulocyte-macrophage colony-stimulating factor receptors by human first trimester extravillous trophoblast and its response to this cytokine.

The present study has demonstrated that human extravillous trophoblast cells isolated from first trimester placentae can bind granulocyte-macrophage colony-stimulating factor (GM-CSF). We have used a technique which incorporates a phycoerythrin (PE)-conjugated GM-CSF in association with a monoclonal antibody against trophoblast (BC-1) in single and double flow cytometric analysis. Trophoblast cells are also observed to show increased DNA synthesis in response to GM-CSF as assayed by [3H]thymidine incorporation and proliferative activity as demonstrated by double immunocytochemical staining of cells with a trophoblast cytokeratin marker (PKK1) and for the nuclear proliferation antigen (Ki-67). These findings provide evidence that human extravillous trophoblast expresses receptors for GM-CSF and responds to this cytokine.