Placental mononuclear phagocytes as a source of interleukin-1

Mouse and human placental tissue contains a large number of mononuclear phagocytes. These cells, isolated from placenta, were shown to produce the multifaceted immune factor interleukin-1. Activity in the supernatants of 48-hour mononuclear phagocyte cultures was associated with a 12,000- to 18,000-dalton protein, consistent with known interleukin-1 characteristics. Stimulation of phagocytosis with latex beads increased the production and release of interleukin-1 from these placental cells, which may be a useful source of this protein.