Azurocidin, also called heparin-binding protein (HBP) or cationic antimicrobial protein of 37 Kda (CAP37), is an inactive homolog of serine proteinases residing in granulocytes. Initially it was thought to have only activity against gram-negative bacteria. Later it was also found to act against gram-positive bacteria and C.albicans. Azurocidin is considered a family member of polymorphonuclear leukocytes- derived antimicrobial proteins like defensins, LL-37 and lysozyme. Azurocidin has been recognized as a player in the activation and modulator of the immune response and may act to alarm the immune system. The cationic domain at one side of the protein is essential for its antimicrobial activity. It is stored in azurophil granules as well as secretory granules and as a result partly released at early stage of extravasation. Azurocidin is involved in chemotaxis and activation of monocytes, cytokine release and phagocytosis leading to more efficient bacterial clearance. The primary targeted environment of azurocidin are cells in the bloodstream, that is the endothelial lining, and the extravascular surroundings. The interaction of azurocidin with leucocytes is mediated via β2-intergrins.
The human Azurocidin ELISA kit is to be used for the in vitro quantitative determination of human azurocidin in plasma, serum and sputum samples.
The human Azurocidin ELISA is a ready-to-use solid-phase enzyme-linked immunosorbent assay based on the sandwich principle with a working time of 3½ hours. The efficient format of a plate with twelve disposable 8-well strips allows free choice of batch size for the assay. Samples and standards are incubated in micro titer wells coated with antibodies recognizing human Azurocidin. Biotinylated tracer antibody will bind to captured human Azurocidin. Streptavidin-peroxidase conjugate will bind to the biotinylated tracer antibody. Streptavidin-peroxidase conjugate will react with the substrate, tetramethylbenzidine (TMB). The enzyme reaction is stopped by the addition of oxalic acid. The absorbance at 450 nm is measured with a spectrophotometer. A standard curve is obtained by plotting the absorbance (linear) versus the corresponding concentrations of the human Azurocidin standards (log). The human Azurocidin concentration of samples, which are run concurrently with the standards, can be determined from the standard curve.