Staphylococcal alpha-toxin synergistically enhances inflammation caused by bacterial components.
This study was performed to investigate the in vivo effects of staphylococcal alpha-toxin on phagocytosis and the secretion of proinflammatory cytokines at local sites of intraperitoneal toxin-challenged mice. A dosage of 45 hemolytic units (HU) of alpha-toxin induced a marked increase in the peritoneal neutrophil count. The toxin caused a 52% decrease in phagocytosis by peritoneal macrophages, compared with that of control mice receiving Staphylococcus aureus particles alone. However, no effect on phagocytosis in neutrophils was observed. A dosage of 45 HU toxin and the synergistic activity of S. aureus particles strongly induced interleukin (IL) 6 secretion but only mildly induced IL-1alpha secretion. The toxin did not induce the secretion of tumor necrosis factor-alpha (TNF-alpha). Interestingly, S. aureus culture supernatant induced the secretion of TNF-alpha in cultured macrophages. These results suggest that alpha-toxin damages the primary host defense system by inducing the oversecretion of IL-1alpha and IL-6, but not TNF-alpha, via a mechanism that requires the synergistic action of bacterial components.
Onogawa
Tsuyoshi
T
Department of Immunology, Kyorin University School of Health Sciences, 476 Miyashita, Hachioji-shi, Tokyo 192-8508, Japan. onogawa@kyorin-u.ac.jp
D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D002478:Cells, Cultured; D004357:Drug Synergism; D006460:Hemolysin Proteins / Q000633:toxicity*; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D009504:Neutrophils / Q000473:pathology; D010538:Peritonitis / Q000139:chemically induced* / Q000473:pathology; D010587:Phagocytosis; D013211:Staphylococcus aureus / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D001427:Bacterial Toxins; D006460:Hemolysin Proteins; D007375:Interleukin-1; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; C021091:staphylococcal alpha-toxin