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Dust mite allergens contain a wide array of biological active
components that are probably related to their allergenicity.
However, very few in vivo studies have been carried out to
clarify the direct influence of dust mite allergens to the
airway per se. In the present study, we examined how dust mite
Dermatopgagoides farinae (Der f) affected the airways of mice.
We intratracheally instilled Der f crude extract to female
BALB/c mice for either a single time or a total of ten times.
We then monitored the morphological changes, IgE antibody
production, cytokine expression, and co-stimulatory molecular
B7 expression in the airways over the course of experiments.
We demonstrated that Der f was a pro-inflammatory agent that
single challenge could elicit an acute neutrophilic inflammation
in the airways accompanying with increased expression of
pro-inflammatory cytokines including TNF-, IL-1, and IL-6.
Upon repeated Der f challenge, a chronic inflammation was
developed that was characterized by increased numbers of
lymphocytes and eosinophils. Histopathologically, goblet cell
and bronchial epithelial cell hyperplasia and increased in the
numbers of mast cells in the submucosa were consistent features
in these mice. Notably, repeated Der f challenge could elicit
IgE antibody production, increase IL-5 concentrations in
bronchoalveolar lavage (BAL) fluids, and enhance B7 molecule
expression on BAL cells, suggesting a provocation of a Th2 type
immune response. Our findings were agreed with those in vitro
studies concerning the properties of dust mite allergens.
Inhalation of a clinical relevant allergen such as Der f without
adjuvant should be the most optimal condition to develop
experimental animal models of allergic lung diseases.
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