title: Natural mycobacteriostatic activity in human monocyte-derived adherent cells.
abstract: The effects of human monocyte maturity on the replication of virulent Mycobacterium tuberculosis were examined. Mycobacteria grew readily in freshly isolated, adherent peripheral blood monocytes and in monocyte-derived macrophages obtained after 7 days in culture, as measured by counts of acid-fast bacilli and colony-forming units. Monocytes cultured for only 3 days before infection, however, were less permissive for the mycobacteria than either uncultured or 7-day cells. The association between the low permissiveness of 3-day cells and superoxide production was examined. Mycobacteria induced only a slight increase in superoxide production during the first 60 min of infection in uncultured and in 3-day cells, and no increase in cells cultured for 7 days before infection. Freshly isolated adherent cells produced small amounts of superoxide in response to phorbol myristate acetate (PMA) stimulation, but PMA-induced superoxide production increased steadily for 7 days. Mycobacteria had no effect on superoxide production by PMA-stimulated adherent cells. These results suggest that the suppressive activity of the 3-day cells is not associated with the production of increased amounts of reactive oxygen species.
mesh_terms: D002470:Cell Survival; D002478:Cells, Cultured; D006801:Humans; D066298:In Vitro Techniques; D008264:Macrophages / Q000276:immunology*; D009000:Monocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000254:growth & development / Q000276:immunology*; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
chemical_list: D013481:Superoxides; D013755:Tetradecanoylphorbol Acetate