During the preclinical study of new therapeutic modality, we evaluate whether the treatment can reverse the established
asthma phenotypes in animal model. However, few have reported on the long term persistence of
asthma phenotypes upon re-challenge with
allergen (secondary challenge) in animal model. We evaluated the persistence of
asthma phenotypes by secondary challenge at different times in previously challenged murine
asthma model. BALB/c mice sensitized by
intraperitoneal injections of 20 micro g of
ovalbumin and 1 mg of
alum on days 1 and 14 were challenged initially by the inhalation of 1%
ovalbumin for 30 min on days 21, 22, and 23. Each group of mice was rechallenged at 5, 7, 9, or 12 weeks after the initial challenge.
Airway hyperresponsiveness, BAL fluid, airway histology and serum
ovalbumin-specific
IgE level were evaluated. Airway
eosinophilia, airway
inflammation and serum
ovalbumin-specific
IgE production persisted upon secondary
allergen challenges at least 12 weeks after the initial challenge. However,
airway hyperresponsiveness persisted only until mice were rechallenged 7 weeks after the initial challenge. Airway
inflammation and
allergen specific
IgE production may persist longer than
airway hyperresponsiveness in a mouse
asthma model of secondary
allergen challenge.