title: Induction of interleukin-10 and down-regulation of cytokine production by Klebsiella pneumoniae capsule in mice with pulmonary infection.
abstract: The role of the capsule of Klebsiella pneumoniae in inducing cytokine production was investigated by comparing the responses of mice with experimentally induced pneumonia caused by capsulate (strain DT-S) or non-capsulate (mutant strain DT-X) K. pneumoniae. Anaesthetised ICR mice were inoculated intranasally. Whereas all DT-S-infected mice died within 3 days, no deaths were observed in DT-X-infected mice by 14 days after infection. During the early stage of infection, interferon-gamma (IFN-gamma) levels in bronchoalveolar lavage fluid (BALF) of DT-X-infected mice were significantly higher than those in DT-S-infected mice. In contrast, in the late stage of infection, serum levels of granulocyte macrophage-colony stimulating factor (GM-CSF) and IFN-gamma in DT-S-infected mice were significantly higher than those in DT-X-infected mice. Levels of interleukin10 (IL-10) in BALF and serum of DT-S-infected mice were significantly and persistently higher than those of DT-X-infected mice. The IL-10/TNF-alpha (tumour necrosis factor-a) ratios in BALF and serum indicated that higher levels of IL-10 production were induced in mice infected with strain DT-S than in those infected with strain DT-X. The results suggest that the capsule of K. pneumoniae may induce IL-10 production at the site of infection and, thereafter, these high IL-10 levels may serve to down-regulate the expression of pro-inflammatory cytokines.
authors.forename: Kanako
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Second Department of Internal Medicine, *Department of Microbiology, and †Department of Hospital Pathology, Toho University School of Medicine, Omori-Nishi, Ota-ku, Tokyo, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Second Department of Internal Medicine, *Department of Microbiology, and †Department of Hospital Pathology, Toho University School of Medicine, Omori-Nishi, Ota-ku, Tokyo, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tateda
authors.forename: Kou
authors.initials: K
authors.lastname: Uchida
authors.affiliation: Second Department of Internal Medicine, *Department of Microbiology, and †Department of Hospital Pathology, Toho University School of Medicine, Omori-Nishi, Ota-ku, Tokyo, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Tsujimoto
authors.affiliation: Second Department of Internal Medicine, *Department of Microbiology, and †Department of Hospital Pathology, Toho University School of Medicine, Omori-Nishi, Ota-ku, Tokyo, Japan.
authors.forename: Keizo
authors.initials: K
authors.lastname: Yamaguchi
mesh_terms: D000818:Animals; D016667:Bacterial Capsules / Q000502:physiology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D016207:Cytokines / Q000097:blood / Q000378:metabolism*; D015536:Down-Regulation; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000097:blood / Q000378:metabolism; D007371:Interferon-gamma / Q000097:blood / Q000378:metabolism; D016753:Interleukin-10 / Q000097:blood / Q000378:metabolism*; D007700:Kinetics; D007710:Klebsiella Infections / Q000378:metabolism / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000502:physiology*; D008168:Lung / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D008171:Lung Diseases / Q000382:microbiology / Q000401:mortality / Q000473:pathology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D013047:Specific Pathogen-Free Organisms; D016019:Survival Analysis; D015996:Survival Rate; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D016207:Cytokines; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor