Electron microscopic studies of the interaction between ovine alveolar macrophages and Mycoplasma ovipneumoniae in vitro

The interaction between Mycoplasma ovipneumoniae and ovine alveolar macrophages with and without the addition of antibody was observed by both scanning and transmission electron microscopy. Mycoplasma ovipneumoniae organisms had the ability to attach to the plasma membrane of macrophages without inducing phagocytosis although they stimulated mitotic division in early cultured cells. The addition of specific antibody to mycoplasma--macrophage cultures stimulated phagocytosis of the organisms. Macrophages stimulated by antibody showed rapid and extensive spreading on the coverslip and their plasma membrane exhibited prominent ruffling. Many openings and fine cytoplasmic pits were also evident. With transmission electron microscopy numerous micro-organisms were seen within phagocytic vacuoles two hours after the addition of antibody.