DEVELOPMENT OF BONE-MARROW EOSINOPHILIA IN MICE INDUCED BY ASPERGILLUS-FUMIGATUS ANTIGENS

A model of allergic bronchopulmonary aspergillosis (ABPA) developed by exposing mice to Aspergillus fumigatus antigen (Af) exhibits peripher al blood (PB), lung, and bone marrow (BM) eosinophilia. Because the BM is a site of eosinophilopoiesis, we have investigated the role of Af in the induction of this process in the BM. Groups of mice were expose d intranasally (i.n.) or intraperitoneally (ip) to Af. BM cells from m ice were cultured with either Af or allogenic spleen cell supernatant stimulated with Af. Eosinophil counts in different lymphoid compartmen ts, eosinophil peroxidase (EPO), and mRNA for cytokines and IgE in BM cells were studied. Results indicate that the eosinophil numbers were significantly elevated in PB and BM of all Af-exposed mice. Lung lavag e eosinophils increased only in the i.n. group. Af induced EPO activit y only in BM cultures from Af-exposed mice. The EPO activity was furth er enhanced by supernatants from spleen cells from Af-exposed mice. mR NA transcription of IL-3 and IL-5 were measurable in BM cells of the i p exposed mice. These findings suggest that Af mediates eosinophil dev elopment in BM of mice and this process is promoted by hematopoietic f actors generated within the BM and in other lymphoid tissue such as th e spleen. (C) 1997 Academic Press.