In vitro multiplication and apparently indefinite subcultures of normal mouse resident peritoneal macrophages

Multiplication of Balb/C mouse resident peritoneal macrophages was observed, when all the cells collected in the washing fluid of the peritoneal cavity were seeded in appropriate culture medium. This multiplication began only after the appearance of a confluent monolayer of flat cells, referred to as "mesothelial" cells. The macrophages produced passed from the "mesothelial" cell layer to the suspension and could be passaged indefinitely. Each culture underwent an identical cycle of events which always included the appearance of a confluent monolayer of "mesothelial" cells. The cells transferred were characterized by their ability to phagocytose yeasts, and by the presence of Fc receptors and cytoplasmic non-specific esterases.