ANTI-INTERLEUKIN (IL)-4 AND ANTI-IL-5 ANTIBODIES DOWN-REGULATE IGE AND EOSINOPHILIA IN MICE EXPOSED TO ASPERGILLUS ANTIGENS

The effect of multiple divided doses compared with single-dose injecti ons of antibodies to murine interleukin (IL)-4 and IL-5 in their respe ctive downregulation of IgE and eosinophilia developing in a model of allergic aspergillosis is investigated. BALB/c mice were exposed to As pergillus fumigatus antigens (Af) before and along with anticytokine a ntibodies. The kinetics of blood eosinophils, eosinophil peroxidase (E PO) in bone-marrow cells, serum levels of IgE and Af-specific antibodi es, Af-induced cytokine production and mRNA, and lung histology were s tudied. The results indicate that only multiple anti-IL-5 antibodies w ere effective in maintaining baseline levels of blood eosinophils. Mul tiple anti-IL-4 antibodies also downregulated eosinophils in the bone marrow lung, and peripheral blood, although to a lesser extent than in anti-IL-5 antibody-injected mice. Significant correlation between the EPO activity and the eosinophil numbers in anticytokine antibody-trea ted mice was observed. The different anti-IL-4 antibody treatments dow nregulated IgE to the same extent. We conclude that multiple divided d oses of anti-IL-5 antibodies are required to sustain normal eosinophil levels in murine allergic aspergillosis. This information may be sign ificant in the therapy of pulmonary allergic diseases.