title: Effects of respiratory Mycoplasma pneumoniae infection on allergen-induced bronchial hyperresponsiveness and lung inflammation in mice.
abstract: Airway mycoplasma infection may be associated with asthma pathophysiology. However, the direct effects of mycoplasma infection on asthma remain unknown. Using a murine allergic-asthma model, we evaluated the effects of different timing of airway Mycoplasma pneumoniae infection on bronchial hyperresponsiveness (BHR), lung inflammation, and the protein levels of Th1 (gamma interferon [IFN-gamma]) and Th2 (interleukin 4 [IL-4]) cytokines in bronchoalveolar lavage fluid. When mycoplasma infection occurred 3 days before allergen (ovalbumin) sensitization and challenge, the infection reduced the BHR and inflammatory-cell influx into the lung. This was accompanied by a significant induction of Th1 responses (increased IFN-gamma and decreased IL-4 production). Conversely, when mycoplasma infection occurred 2 days after allergen sensitization and challenge, the infection initially caused a temporary reduction of BHR and then increased BHR, lung inflammation, and IL-4 levels. Our data suggest that mycoplasma infection could modulate both physiological and immunological responses in the murine asthma model. Our animal models may also provide a new means to understand the role of infection in asthma pathogenesis and give evidence for the asthma hygiene hypothesis.
authors.affiliation: Department of Medicine, National Jewish Medical and Research Center, Denver, Colorado, USA.
authors.forename: Hong Wei
authors.initials: HW
authors.lastname: Chu
authors.forename: Joyce M
authors.initials: JM
authors.lastname: Honour
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Rawlinson
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Harbeck
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Martin
mesh_terms: D000485:Allergens / Q000276:immunology*; D000818:Animals; D001249:Asthma / Q000209:etiology*; D016535:Bronchial Hyperreactivity / Q000209:etiology*; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000276:immunology; D011019:Pneumonia, Mycoplasma / Q000276:immunology*
chemical_list: D000485:Allergens; D015847:Interleukin-4; D007371:Interferon-gamma; D010047:Ovalbumin