Phagocytosis and Intracellular Fate of Mycobacterium Tuberculosis: In Vitro Studies with Guinea Pig Peritoneal and Alveolar Mononuclear Phagocytes

Summary The role of cellular immunity in tuberculosis was studied by using in vitro techniques to observe cellular capacities for phagocytosis and bacterial inactivation. Peritoneal exudates were stimulated and collected and alveolar phagocytes were harvested using standard techniques. Normal and BCG-immunized guinea pigs were used as phagocyte donors. Two strains (H37Rv, H37Ra) of Mycobacterium tuberculosis were used for infecting the phagocytes. Suspensions of these tubercle bacilli consisting of single cells were prepared by filtration. Plate counts were used to indicate the amount of ingestion and cytopepsis by the phagocytes. It was shown using the H37Rv strain of tubercle bacilli that phagocytes from BCG-immunized animals had increased cytopeptic activity when compared to phagocytes from normal animals. Also, the alveolar phagocytes were more active in cytopepsis than were the peritoneal exudate cells.