Respiratory hypersensitivity to Ascaris extract in guinea pigs sensitized by aerosol.

Guinea pigs exposed via the respiratory route to Ascaris suum extract in aerosol form became hypersensitive. The hypersensitivity was detectable by inhalational bronchial provocation testing using a noninvasive plethysmography, 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.