A new technique for the isolation of placental phagocyte cells and a description of their macrophage properties after in vitro culture.

We describe a method for the separation of phagocytic cells from human placenta by mechanical stirring for 2 h in the absence of proteolytic enzymes. About 60% of the cells were separated by adherence to glass. These adherent macrophage-like cells were able to ingest solid particles; 17% of them phagocytized opsonized sheep red cells and 96% ingested Staphylococcus aureus. IgGFc receptors were expressed in 22% of these cells and C3b receptors in 62% of them. Ultrastructural studies of adherent cells revealed different cells of varying shapes and sizes containing lysosomal granules, heterophagosomes and residual bodies. The cells were peroxidase-negative.