Purity ≥96% as determined by SDS-PAGE and HPLC. In response to the presence of allergens, this protein directly promotes the accumulation of eosinophils (a prominent feature of allergic inflammatory reactions), but not lymphocytes, macrophages or neutrophils. Biological Activity: Fully biologically active when compared to standard. The biological activity determined by a chemotaxis bioassay using purified eosinophils is in a concentration range of 100-1000ng/ml.