Collaborative studies with the Allergy and Inflammation Research Group and the Gene Targeting Laboratory on the role of IL-5 in allergic lung disease have continued. The present emphasis is to define the roles played by IL-5 and eotaxin in regulating eosinophilic inflammation and airways hyperresponsiveness using mice deficient in one or both cytokines. The results indicate that eosinophils play a key role in the orchestration of allergic inflammation and airways dysfunction. These and other studies carried out by the Cytokines and Inflammation Group, have formed the basis of our NH&MRC Program Grant on the Molecular Mechanisms in the Regulation of Allergy and Inflammation which starts in 2003.