PURIFICATION AND CHARACTERIZATION OF A NEW CATIONIC PROTEIN EOSINOPHIL PROTEIN-X (EPX) FROM GRANULES OF HUMAN EOSINOPHILS

  • 1 January 1983
    • journal article
    • research article
    • Vol. 50  (1) , 19-26
Abstract
The isolation and characterization of a new eosinophil-derived protein, eosinophil protein X (EPX), is described. The purified EPX is a highly basic glycoprotein and shows 1 band on sodium dodecyl sulfate polyacrylamide gel electrophoresis and on agarose electrophoresis. The MW of the unreduced protein was 23,000 and after reduction 19,000. EPX did not precipitate antibodies prepared to other eosinophil-derived proteins such as eosinophil cationic protein (ECP) or major basic proteins (MBP) or antibodies prepared to a number of neutrophil-derived proteins. The eosinophil origin of EPX was indicated by the linear correlation between the amount of EPX and the percentage of eosinophils in mixed leukocyte extracts prepared from normal individuals. The EPX content averaged 10 .mu.g/106 normal eosinophils. EPX from normal eosinophils and from eosinophils from 1 patient with hypereosinophilia seemed to be identical.