title: Phagocytosis of heat-killed radiolabelled mycobacteria in human mononuclear phagocytes cultured in vitro.
abstract: Human mononuclear phagocytes cultured in vitro for 8 dyas were exposed to 125I-labelled, heat-killed Mycobacterium triviale. The microorganisms were apparently engulfed, but no digestion occurred within a period of 16 days after the engulfment, measured as release of radioactivity to the medium and observed microscopically. Attempts were made to stimulate intracellular digestion of the bacteria. Pre-incubation with BCG-stimulated lymphocytes or with supernatants from BCG-stimulated lymphocyte cultures did not increase the digestive ability of the cells. However, pre-incubation with BCG-stimulated lymphocytes or with supernatants caused detachment of the cells during the following digestion period, probably due to a cytotoxic effect of autologous, transformed lymphocytes on macrophages. When the macrophages were cultured in the presence of autologous lymphocytes and BCG, a similar effect was found.
mesh_terms: D001500:BCG Vaccine; D002478:Cells, Cultured; D006801:Humans; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000276:immunology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D009161:Mycobacterium / Q000276:immunology*; D009163:Mycobacterium bovis; D010587:Phagocytosis
chemical_list: D001500:BCG Vaccine