Transformation of Hamster Macrophages into Giant Cells with Antimacrophage Serum

THE sequence of cellular changes leading from monocyte to macrophage, epithelioid cell and finally multinucleated giant cell is now well documented both in vitro and in vivo. These changes, however, occur only in prolonged culture and in normal conditions only a small number of cultured macrophages have a tendency to undergo such transformation^1,2. It is known that antimacrophage serum (AMS) has a marked influence on the physiology of the macrophage, the target structure probably being the cell membrane³. Agglutination of macrophages and decrease in the rate of phagocytosis have been described by several authors^3,4. Moreover, Unanue⁴ found macrophages showing aberrant nuclear changes in the peritoneal cavity of AMS-treated mice. This report concerns the influence of the protracted action of AMS on the development of giant cells in the cultures of mouse and hamster peritoneal macrophages.