Intracellular antibody neutralizes Listeria growth.
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.
Edelson
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Department of Pathology and Immunology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8118, St. Louis, MO 63110, USA.
Unanue
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D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology* / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D000942:Antigens, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology; D001427:Bacterial Toxins; D002478:Cells, Cultured; D003600:Cytosol / Q000276:immunology; D005260:Female; D006360:Heat-Shock Proteins / Q000276:immunology*; D006460:Hemolysin Proteins; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D007424:Intracellular Fluid / Q000276:immunology; D008089:Listeria monocytogenes / Q000254:growth & development / Q000276:immunology*; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009500:Neutralization Tests; D015398:Signal Transduction / Q000276:immunology
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D007371:Interferon-gamma; C038705:hlyA protein, Listeria monocytogenes