Abstract
Abstract Eosinophil cationic protein (ECP) is one of the proteins in the ribonuclease A (RNase A) superfamily that have developed various biological properties related to the function of eosinophils. ECP secreted by activated human eosinophils that has anti-parastic, antibacterial, and neurotoxic activities. It is a potent cytotoxic molecule, and the mechanism remains unknown. Reported study suggest that growth inhibition by ECP is dependent on cell type and is cytostatic. In allergic inflammatory process is associated almost invariably with tissue damage and healing. The respiratory epithelium is an essential target of the inflammatory attack by eosinophils in asthma. Bronchial epithelial cells show morphological characteristics of apoptosis mediated by activated eosinophils. To determine the cytotoxic effect of ECP on BEAS-2B cells line. A method for producing recombinant ECP in a prokaryotic expression system was devised. Periplasmic isolates from induced bacterial transfectants contained enzymatically active ECP; micromolar concentration of ECP were shown to be toxic for BEAS-2B cells line. As the data shown, we find that the ECP treatment on BEAS-2B cells has apoptotic effect. The result match to apoptosis induced in inflammatory tissue and allergic disease by activated eosinophils. Due to report study, the RNase activity of ECP companies to its neurotoxic activities, but opposite to its anti-parasite and antibacteridal activity. During our experiment, we decreased the RNase activity of ECP by site direct mutation for further test.