Effects of immune lymphocyte products and serum antibody on the multiplication of Toxoplasma in murine peritoneal macrophages.

In vitro studies on cell-mediated immunity against Toxoplasma infection were carried out by estimating the ability of antigenically stimulated lymphocytes. Splenic lymphocytes from normal mice and from hyper-immunized mice were cultured in the presence or absence of Toxoplasma lysate antigen. The cell-free supernatant fluids from the lymphocyte cultures were assassed for their ability to alter the functional capacities of normal macrophages. When glycogen-induced peritoneal macrophages were incubated with the culture supernatant from immune lymphocytes reacting with specific angigen, the intracellular multiplication of the organisms was inhibited remarkably. In contrast, the addition of antitoxoplasma antibody to culture medium had no effect on the enhancement of phagocytic activity of culture macrophages. However, when extra-cellular organisms were exposed to fresh or heat-inactivated immune serum just before infection of the monolayers, the intracellular multiplication of Toxoplasmas was inhibited significantly by either activated or normal macrophages.