Evidence for the non-peptide nature of neutrophil-derived eosinophil chemotactic factor

Neutrophil-derived low molecular weight eosinophil chemotactic factor (ECFPMN) was examined by a number of methods to prove its peptide nature. Sephadex G-10 eluates of ECFPMN were analyzed by paper chromatography and thin-layer chromatography, and peptides were separated on a peptide analyzer. Peptides isolated by these three different methods have no neutrophil or eosinophil chemotactic activity over a wide range of concentrations. Enzyme digestion studies supported these findings. Other physical and biological properties of ECFPMN suggest that this material is most likely lipid in nature.