Interaction of Mycoplasma pulmonis with mouse peritoneal macrophages and polymorphonuclear leucocytes.

Mouse peritoneal macrophages and polymorphonuclear leucocytes were examined for their ability to kill Mycoplasma pulmonis in vitro. Killing of mycoplasmas was shown to require specific antibody, suggesting that antibody-dependent phagocytosis may be involved in resistance to infection. Convalescent mouse serum appeared to be less effective than rabbit antiserum in promoting the killing of mycoplasmas by phagocytic cells. Moreover, mycoplasmas recovered directly from the respiratory tract of infected mice were more resistant to killing by macrophage cultures than organisms grown in vitro. The possibility that these observations may contribute to an understanding of the persistent nature of M. pulmonis infections in mice is discussed.