Murine Study Demonstrates Protection Against Allergen-Mediated Airway Pathology

A new study reveals that exposure to dog-associated household dust results in protection against airway allergen challenges by causing changes in gut microbes.

Researchers at the University of California-San Francisco (UCSF; USA) and the University of Michigan (Ann Arbor, USA), using murine models, succeeded in demonstrating that exposure of mice to dog-associated house dust protects against ovalbumin or cockroach allergen-mediated airway pathology. The protected mice exhibited significant reduction in the total number of airway T cells, down-regulation of Th2-related airway responses, and a reduction of mucin secretion. The researchers then examined the mice to determine why the changes occurred.

The found that the cecal microbiome of the exposed mice was extensively restructured with significant enrichment of, amongst others, Lactobacillus johnsonii. The Lactobacilli protected them against airway allergen challenge or infection with respiratory syncytial virus (RSV) infection, which has been linked with elevated asthma risk when experienced in infancy. The L. johnsonii-mediated protection was associated with significant reductions in the total number and proportion of activated CD11c+/CD11b+ and CD11c+/CD8+ cells. The study was published on December 16, 2013, in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

“Gut microbiome manipulation represents a promising new therapeutic strategy to protect individuals against both pulmonary infection and allergic airway disease,” said lead author professor Susan Lynch, MD, of the division of gastroenterology at UCSF. “The composition and function of the gut microbiome strongly influence immune reactions and present a novel avenue for development of therapeutics for both allergic asthma and a range of other diseases.”

Exposure of children to dogs in early infancy has been shown to reduce the risk of childhood allergic disease development, and dog ownership is associated with a distinct house dust microbial exposure.

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University of California-San Francisco
University of Michigan