ROLE OF PARTICULATE ANTIGENS OF ASPERGILLUS IN MURINE EOSINOPHILIA

Objective: Allergic bronchopulmonary aspergillosis, a disabling hypers ensitivity lung disease, results from inhalation of Aspergillus fumiga tus antigens present in contaminated environments. A murine model has been developed to understand the immune mechanism involved in allergic bronchopulmonary aspergillosis. We have investigated the immunoregula tory role of different physical forms of A. fumigatus antigens, such a s A. fumigatus spores, soluble antigens, and soluble antigen coupled i nert particles, in the model. Methods: BALB/c mice were exposed to sol uble A. fumigatus antigens, spores, or inert particles of comparable s ize to the spores coupled with A. fumigatus soluble antigens. Antibody and eosinophil response, pulmonary pathology, and cytokine expression s were studied. Results: Peripheral blood eosinophilia and pulmonary i nflammation with influx of eosinophils into the lung was detected more in animals exposed to particulate antigens than in those exposed to s oluble antigen. However, the total serum IgE and Aspergillus-specific IgG levels showed only a slight increase in the former groups as oppos ed to elevated levels in animals exposed to soluble antigen. The cytok ine expression in in vitro antigen stimulated spleen cells showed a ty pical Th2 pattern in all antigen-exposed animals. IL-5 mRNA could be d etected in the spleen cells cultured with antigen from all groups of a ntigen-exposed animals. Conclusion: Particulate A. fumigatus antigens induced eosinophilia in mice prior to the elevation of serum IgE level s. This pattern of IgE and eosinophilia is reversed with the soluble a ntigen exposure in this model.