Bronchial sensitization in guinea pigs following ingestion of ovalbumin

Local bronchial mucosal hypersensitivity following antigen feeding was studied in the guinea pig. Groups of 6 animals were fed 1% ovalbumin (OA) in tap water or tap water without antigen (control group) for different feeding periods (14, 28, 42, and 56 days). Inhalative provocations with increasing concentrations of OA (0.5-8% OA) were performed at the end of each feeding period followed by body plethysmographic measurement of airway obstruction. Specific bronchial hypersensitivity to inhaled OA was not found in the control group, whereas specific bronchial reactivity to OA, described as reactivity index, was significantly different from the control group after 14 (p less than 0.05), 28 (p less than 0.001) and 42 days (p less than 0.01) of feeding. No difference to the control group was found after 56 days of feeding. Anti-OA IgG total and IgG1 in serum and bronchoalveolar lavage fluid were increased in OA-fed animals reaching maximal concentrations at day 28 of the feeding period. We conclude that oral feeding of a 1% solution of OA can induce a transient state of local hypersensitivity to inhaled antigen in the guinea pig as manifested by bronchoconstriction on OA inhalation and increased concentrations of local and systemic specific antibodies. This period of local hypersensitivity is followed by tolerance.