EOSINOPHIL CATIONIC PROTEIN (ECP)

ECP (eosinophil cationic protein) was first purified from human myleoi d cells in 1971 and identified as an eosinophil granule protein in 197 5. ECP is a heterogeneous protein with molecular weights of the varian ts from 16-24 kDa. ECP is extremely basic with a pI of pH 10.8. The ge ne for ECP is found on chromosome 14 adjacent to other proteins of the ribonuclease family, with which ECP shares some sequence homologies. ECP has a variety of biological activities interacting with other immu ne cells and plasma proteins such as coagulation factors and proteins of the complement system. The cytotoxic activity, however, is the most conspicuous. The different isoforms of ECP seem to have different bio logical properties with respect to cytotoxicity and the effects on fib roblasts. ECP can be measured in biological fluids, by means of sensit ive immunoassays, as an indication of eosinophil turnover and activity in vivo. (C) 1998 Elsevier Science Ltd. All rights reserved.