To create an allergy model in the dog, allergic Beagles with high levels of
serum immunoglobulin E (IgE) and eosinophilia were bred; resulting puppies
were sensitized to ragweed by intraperitoneal (IP) injection within 24 hou
rs of birth through 22 weeks of age. At least 50% of the puppies developed
high levels of serum IgE and eosinophilia. As young adults, 6 of these dogs
, and 6 control age-matched, nonallergic, nonimmunized dogs were exposed by
inhalation to ragweed twice at 13-day intervals, and a third time 45 days
later. Total and ragweed-specific serum IgE and ragweed-specific serum IgE
were increased significantly in allergic dogs relative to baseline. Allergi
c dogs had significantly greater levels of antibody specific for ragweed, a
s well as higher eosinophil counts in the bronchoalveolar lavage fluid, com
pared to nonallergic dogs. Airway reactivity to histamine in allergic, but
not nonallergic dogs, increased significantly after aerosol exposure to rag
weed. After a third exposure to ragweed, airway responses to histamine were
elevated in the allergic dogs and remained high for at least 5 months. The
se results demonstrate the potential of the allergic dog model for investig
ating the underlying pulmonary immune mechanisms and therapeutic treatment
of allergic asthma.