Matthew D Woolard1, R Doug Hardy, Jerry W Simecka. 1. Department of Molecular Biology and Immunology, University of North Texas Health Science, Center, Fort Worth, TX 76107, USA.
Abstract
BACKGROUND: Mycoplasma respiratory infections are associated with wheezing and exacerbation of airway hyperresponsiveness (AHR) in asthmatic patients. IL-4 is a key cytokine in the development of AHR and airway reconstruction in asthmatic patients and might be an important component in exacerbation of AHR during pulmonary mycoplasma infection. OBJECTIVE: This study evaluates the effect of IL-4 on the severity of methacholine-induced AHR associated with mycoplasma pulmonary mycoplasma infection. METHODS: BALB/c and IL-4 knockout (KO) mice were infected with Mycoplasma pulmonis, and their enhanced pause scores were monitored before and after methacholine inhalation with whole-body plethysmography. RESULTS: IL-4 KO mice showed no difference in histopathology of the lungs before or after Mycoplasma pulmonis infection when compared with BALB/c mice. There was an increase in airway obstruction from days 7 to 21 after infection in both strains of mice, but there was no strain difference in airway resistance-associated mycoplasma disease. However, IL-4 KO mice had significantly higher methacholine-induced AHR after M pulmonis infection when compared with BALB/c mice. There was no difference in AHR between uninfected IL-4 KO and control mice. CONCLUSION: In contrast to our hypothesis, IL-4-independent pathways exacerbate methacholine-induced AHR and promote airway obstruction during the pathogenesis of mycoplasma respiratory disease.
BACKGROUND:Mycoplasma respiratory infections are associated with wheezing and exacerbation of airway hyperresponsiveness (AHR) in asthmatic patients. IL-4 is a key cytokine in the development of AHR and airway reconstruction in asthmatic patients and might be an important component in exacerbation of AHR during pulmonary mycoplasma infection. OBJECTIVE: This study evaluates the effect of IL-4 on the severity of methacholine-induced AHR associated with mycoplasma pulmonary mycoplasma infection. METHODS: BALB/c and IL-4 knockout (KO) mice were infected with Mycoplasma pulmonis, and their enhanced pause scores were monitored before and after methacholine inhalation with whole-body plethysmography. RESULTS:IL-4 KO mice showed no difference in histopathology of the lungs before or after Mycoplasma pulmonis infection when compared with BALB/c mice. There was an increase in airway obstruction from days 7 to 21 after infection in both strains of mice, but there was no strain difference in airway resistance-associated mycoplasma disease. However, IL-4 KO mice had significantly higher methacholine-induced AHR after M pulmonis infection when compared with BALB/c mice. There was no difference in AHR between uninfected IL-4 KO and control mice. CONCLUSION: In contrast to our hypothesis, IL-4-independent pathways exacerbate methacholine-induced AHR and promote airway obstruction during the pathogenesis of mycoplasma respiratory disease.
Authors: Chonnamet Techasaensiri; Claudia Tagliabue; Marianna Cagle; Pooya Iranpour; Kathy Katz; Thirumalai R Kannan; Jacqueline J Coalson; Joel B Baseman; R Doug Hardy Journal: Am J Respir Crit Care Med Date: 2010-05-27 Impact factor: 21.405
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