Hyperimmune serum modulates allergic response to spores in a murine model of allergic aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is a disease in atopic asthmatics characterized by eosinophilia and elevated levels of immunoglobulin E (IgE) and IgG antibodies to the ubiquitous fungus Aspergillus fumigatus (Af). The role of specific antibodies in the disease process is not clear. In this study, BALB/c mice were injected with hyperimmune serum from syngeneic mice exposed to soluble antigen of Af. These mice were then exposed to either Af spores or soluble antigen. Total IgE, Af-specific IgG1 (enzyme-linked immunosorbent assay) in serum, and eosinophils (eosinophil peroxidase assay) in lungs and bone marrow were measured. Histologic sections of lungs were examined for cellular infiltration and morphologic changes. Results indicate a suppression of increase in levels of antibodies and eosinophilia in mice receiving immune serum and exposed to spores compared with controls receiving phosphate-buffered saline treatment. Spores being the primary source of exposure to Af in ABPA, these results are significant in understanding the role of preexisting specific antibodies in patients.