Isolation and partial characterization of an eosinophil chemotactic factor from metacestodes of Taenia taeniaeformis (ECF-Tt)

Eosinophil chemotactic activity associated with protein extracts of Taenia taeniaeformis metacestodes was investigated. Chemotactic activity was associated with the nonbound protein after QAE cellulose chromatography of a 3 M KCl extract of homogenized larvae. When this material was precipitated with ammonium sulfate, activity was present in the 40 to 80% precipitate. Upon rechromatography on QAE cellulose equilibrated in a low ionic strength buffer, eosinophil chemotactic activity was retained by the gel and eluted after application of the NaCl gradient. Gel filtration of Sephacryl S-300 yielded an estimated m.w. of 91,000. Chromatofocusing revealed a broad peak of activity with a pI of 4.5 to 5.0. SDS-PAGE showed the active fraction migrated as a protein with a m.w. of 10,400. ECF-Tt had chemotactic and chemokinetic activity for equine eosinophils and murine eosinophils, but not for equine and murine neutrophils.