Studies have also continued on the mechanisms regulating IL-5 gene expression in T lymphocytes. This expression is both tissue-specific and inducible and is very relevant to the eosinophil-mediated tissue damage which occurs in asthma and allergy. Jun Wang established transient expression systems in both mouse and human T cells and carried out comprehensive transactivation studies to identify the transcription factors and the binding sites involved in the regulation of the mouse and human IL-5 genes. The results suggest the formation of an enhanceosome type complex in the proximal promoter region involving the transcription factors GATA-3, AP-1 and Ets and possibly also HMGI(Y) which regulates inducible and tissue-specific gene expression. The involvement of MAP kinase pathways in IL-5 induction has also been studied.