Guinea pigs exposed via the respiratory route to Ascaris suumextract in aerosol form became hypersensitive. The hypersensitivity was detectable by inhalational bronchial provocation testing using a noninvasive plethysmograph, by chopped lung histamine release, and by passive cutaneous anaplylaxis. The antibody responsible for the hypersensitivity seems to be directly associated with pulmonary tissue. A locally produced cytotropic pulmonary antibody, probably IgG or IgE may be causal. Histopathology included only a moderate pulmonary eosinophilia. Individual variability in susceptibility to experimental allergic asthma may be controlled by both physiologic and immunologic reactivities.
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