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The timing of exposure of mononuclear phagocytes to recombinant interferon γ and recombinant tumor necrosis factor α alters interactions with Nocardia asteroides
Author(s) -
Beaman LoVelle,
Beaman Blaine
Publication year - 1992
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.51.3.276
Subject(s) - phagocyte , biology , microbiology and biotechnology , phagocytosis , nocardia , tumor necrosis factor alpha , mononuclear phagocyte system , coccidioides immitis , lipopolysaccharide , macrophage , interferon , in vitro , immunology , bacteria , biochemistry , genetics
Nocardia asteroides modulates phagocyte function and grows within macrophages. Because interferon γ (IFN‐γ) and tumor necrosis factor α (TNF‐α) have been shown to activate macrophages to kill a variety of microorganisms, the effects of IFN‐γ and TNF‐α on the activation of murine macrophages and human monocytes to kill nocardiae were studied. It was found that macrophages or monocytes treated with either IFN‐γ, TNF‐α, or lipopolysaccharide as a secondary signal did not demonstrate increased microbicidal activity against N. asteroides even though these phagocytes were effective at killing the fungus Coccidioides immitis and the protozoan Toxoplasma gondii. Preincubation of phagocytes for 24 h with these compounds resulted in an enhancement of nocardial growth. In contrast, coincubation of these factors with the nocardiae and mononuclear cells during phagocytosis resulted in inhibition of nocardial growth even though this bacterium was not killed. Therefore, the specific timing of the exposure of the phagocyte in vitro to IFN‐γ or TNF‐α has a significant effect on its ability to alter nocardial growth.