A rabbit model of hypersensitivity to plicatic acid, the agent responsible for red cedar asthma.

We describe a rabbit model for the study of the immunogenicity and allergenicity of plicatic acid (PA), the small molecular weight compound in western red cedar responsible for occupational asthma in exposed workers. Specific anti-PA IgE as well as IgG antibodies could be raised, depending on the method of immunization. The sensitized rabbits reacted to antigenic challenge with PA-protein conjugates intravenously, with increases in respiratory frequency and pulmonary resistance. This animal model may be used for the further elucidation of the mechanism of occupational asthma induced by small molecular weight chemical compounds.