Isolation and characterization of Hofbauer cells from human placental villi.

Hofbauer cells are a major cell type of the human placental villous core and they are particularly numerous at the beginning of pregnancy. In the present study we describe a method suitable to obtain HC suspensions in a highly purified form. These suspensions have been analyzed for surface markers using a battery of monoclonal antibodies. Of all the surface markers used, Hofbauer cells were only positive for 4F2, LeuM2 and LeuM3 monoclonals which mainly detect cells of the monocyte-macrophage lineage. Hofbauer cells were consistently negative for HLA-DR antigens, C3bR and T- or B-cell markers. Hofbauer cells appeared capable of phagocytosing latex beads, adhering to and spreading over plastic surface and secreting lysozyme. In contrast, they failed to originate an efficient respiratory burst in response to appropriate stimulation. Hofbauer cells were positive for ANAE with a perinuclear localization of the enzyme activity, but consistently negative for peroxidase. These observations suggest that they share a number of features with cells of the monocyte-macrophage lineage and yet have some distinctive properties.