Effect of monoclonal antibodies on phagocytosis and killing of Toxoplasma gondii by normal macrophages.

Treatment of intact toxoplasma tachyzoites with individual mouse monoclonal antibodies to toxoplasma which are directed against individual membrane-associated antigenic determinants facilitated the phagocytosis of toxoplasma and also prepared the toxoplasma for intracellular destruction by nonelicited mouse peritoneal macrophages. In instances in which the organisms survived intracellularly, their multiplication was significantly reduced. Such monoclonal antibodies should be useful in further elucidating the role of antibody in resistance to toxoplasma and other facultative and obligate intracellular organisms.