Peritoneal exudate mononuclear phagocyte colony-forming cells: their proliferative state in vivo and sensitivity to cytotoxic agents.

We investigated the proliferative state of peritoneal exudate macrophage colony-forming cells (PE-CFC) by exposing them to [3H]thymidine with a high specific activity in vitro and by administering cytosine arabinoside and methotrexate in vivo. Since [3H]TdR had no appreciable killing effect on PE-CFC and since the drug treatment caused no reduction in the appearance of PE-CFC, we concluded that the majority of PE-CFC, if not all, are not in active cell cycle. The production of PE-CFC was, however, suppressed by the administration of nitrogen mustard, cyclophosphamide, BCNU and vinlastine.