Abstract
We previously reported that treatment of mice with a neutralizing mAb against listeriolysin O (LLO), the pore-forming toxin of Listeria monocytogenes, provided resistance to this intracellular bacterium. We evaluated whether anti-LLO mAb would affect Listeria handling by macrophages, essential cells in Listeria resistance. Macrophages infected in the presence of anti-LLO mAb showed a marked reduction in intracellular Listeria growth, with a concomitant block in LLO-dependent Listeria passage from phagosome to cytosol. Anti-LLO mAb did not opsonize Listeria but, rather, acted within macrophages to neutralize LLO. Importantly, anti-LLO mAb effects on Listeria growth were independent of Fcgamma receptor expression, IFNgamma signaling, and production of nitric oxide and superoxide. These results identify a novel mechanism for antibody control of bacteria within macrophages.
MeSH terms
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Animals
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Antibodies, Bacterial / immunology*
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Antibodies, Bacterial / pharmacology
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Antibodies, Monoclonal / immunology
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Antibodies, Monoclonal / pharmacology
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Antigens, Bacterial / immunology
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Bacterial Proteins / immunology
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Bacterial Toxins*
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Cells, Cultured
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Cytosol / immunology
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Female
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Heat-Shock Proteins / immunology*
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Hemolysin Proteins
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Humans
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Interferon-gamma / immunology
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Intracellular Fluid / immunology
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Listeria monocytogenes / growth & development
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Listeria monocytogenes / immunology*
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Macrophages, Peritoneal / cytology
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Macrophages, Peritoneal / immunology
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Macrophages, Peritoneal / microbiology
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Male
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Mice
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Mice, Inbred BALB C
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Mice, Inbred C57BL
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Neutralization Tests
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Signal Transduction / immunology
Substances
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Antibodies, Bacterial
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Antibodies, Monoclonal
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Antigens, Bacterial
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Bacterial Proteins
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Bacterial Toxins
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Heat-Shock Proteins
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Hemolysin Proteins
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Interferon-gamma
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hlyA protein, Listeria monocytogenes