Lymphoid Cells in Delayed Hypersensitivity II. In Vitro Phagocytosis and Cellular Immunity.

Guinea pigs which develop delayed hypersensitivity, as measured by skin test, after intraperitoneal infection with Candida albicans have mononuclear cells (macrophages and lymphocytes) which show migration inhibition in vitro in the presence of soluble antigen. Macrophages from such animals phagocytose in vitro fewer numbers of C. albicans per cell than those of normal animals, and lower numbers of macrophages are phagocytic in vitro. Nevertheless, such sensitized animals have lower numbers of pathogens in their tissues than the controls, after both groups have been challenged. Thus, the result of macrophages from sensitized guinea pigs being less mobile, less phagocytic, and more destructive than those from normal animals may be a more limited spread of the infectious agent throughout the tissues; the animal would seem more resistant.