The EDN ELISA Kit measures Human EDN by sandwich ELISA. This ELISA detects Human EDN with a minimum detection limit of 0.62 ng/mL and does not cross-react with ECP.
Samples to be measured or standards are incubated in the wells coated with anti-human EDN monoclonal antibody. After washing, the peroxidase conjugated anti-human EDN polyclonal antibody is added into the microwells and incubated. After another washing, the peroxidase substrate is mixed with the chromogen and allowed to incubate for an additional period of time. An acid solution is added to each microwell to terminate the enzyme reaction and to stabilize the color development. The optical density (O.D.) of each microwell is measured at 450 nm using a microplate reader. The concentration of Human EDN is calibrated from a dose response curve based on the reference standards.
Upon activation, eosinophils secrete several cationic proteins including major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil peroxidase (EPO) and eosinophil-derived neurotoxin (EDN). EDN, also called eosinophil protein X (EPX), is a glycosylated single-chain protein with a molecular weight 18-21 kDa and is a member of the ribonuclease superfamily along with ECP11)-13). Although EDN has high sequence homology to ECP, EDN has 100-fold greater ribonuclease activity than ECP and neurotoxicity but not cytotoxicity9,10. Eosinophil activation has been found to play an important role in inflammatory processes in allergic diseases. EDN can be a marker of eosinophil activation and degranulation. The “EDN ELISA Kit” is a useful reagent for specifically measuring Human EDN with high sensitivity by ELISA.