title: Lung-specific transgenic expression of KC enhances resistance to Klebsiella pneumoniae in mice.
abstract: A vigorous host response is required to effectively clear pathogenic bacteria from the lungs and is dependent upon the recruitment and activation of neutrophils and macrophages. A family of chemotactic cytokines, referred to as chemokines, have been shown to participate in this complex protective response. In this study, we assessed the role of the C-X-C chemokine KC in lung antibacterial host defense using wild-type (wt) B6D2 mice or transgenic mice that had been bred on a B6D2 background expressing KC under the control of a Clara cell-specific promoter within the lung. The administration of Klebsiella pneumoniae to both wt and KC-transgenic mice resulted in a time-dependent expression of KC protein within the lung that peaked at 24 to 48 h postinoculation. When infected with K. pneumoniae, the KC-transgenic mice showed a striking improvement in survival compared with wt control mice. This improved survival was due to an increase in bacterial clearance, which occurred in association with a vigorous recruitment of neutrophils in the KC-transgenic mice compared with their wt control counterparts. No differences in the lung levels of the specific cytokines TNF-alpha, IFN-gamma, IL-12, and IL-10 were noted. However, inducible macrophage inflammatory protein-2 levels were significantly decreased in the KC-transgenic mice compared with the wt mice. This study indicates that the compartmentalized overexpression of KC in vivo results in increased lung bacterial clearance and improved survival, which occurs in association with enhanced polymorphonuclear leukocyte influx to the lung.
authors.affiliation: Department of Medicine, University of Michigan Medical School, Ann Arbor 48109, USA.
authors.forename: W C
authors.initials: WC
authors.lastname: Tsai
authors.forename: R M
authors.initials: RM
authors.lastname: Strieter
authors.forename: J M
authors.initials: JM
authors.lastname: Wilkowski
authors.forename: K A
authors.initials: KA
authors.lastname: Bucknell
authors.forename: M D
authors.initials: MD
authors.lastname: Burdick
authors.forename: S A
authors.initials: SA
authors.lastname: Lira
authors.forename: T J
authors.initials: TJ
authors.lastname: Standiford
mesh_terms: D000276:Adjuvants, Immunologic / Q000235:genetics*; D000818:Animals; D002465:Cell Movement / Q000276:immunology; D054360:Chemokine CXCL1; D019743:Chemokines, CXC / Q000096:biosynthesis / Q000235:genetics*; D002630:Chemotactic Factors / Q000096:biosynthesis / Q000235:genetics*; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology*; D006133:Growth Substances / Q000096:biosynthesis / Q000235:genetics*; D007113:Immunity, Innate; D036341:Intercellular Signaling Peptides and Proteins; D007442:Intubation, Intratracheal; D007710:Klebsiella Infections / Q000276:immunology* / Q000382:microbiology / Q000401:mortality / Q000473:pathology; D007711:Klebsiella pneumoniae / Q000276:immunology*; D008168:Lung / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008822:Mice, Transgenic; D018410:Pneumonia, Bacterial / Q000276:immunology / Q000382:microbiology / Q000401:mortality / Q000473:pathology; D019076:Transgenes / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors; C475895:Cxcl1 protein, mouse; D016207:Cytokines; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins