MYELOPEROXIDASE (MPO) ELISA KIT
INTENDED USE
The Myeloperoxidase (MPO) ELISA Kit is intended for the quantitativedetermination of MPO (Myeloperoxidase) in serum and plasma. It is for in vitro diagnostic useonly.
SUMMARY AND EXPLANATION OF THE TEST
MPO is part of the defence mechanism of the polymorphonuclear leukocytes against exogenic substances. During bacterial infection, these leukocytes, are stimulated by chemotactically effective substances (leukotrienes, complement factors, bacterial toxins etc.). They move to the site of the infection and encapsulate the foreign substances. If the foreign agent is located in an intracellular vacuole, different substances are used for the intracellular digestion. Amongst these are MPO, cationic proteins, lysozyme, lactoferrin and some acidic hydrolases. A strong surge of oxidative metabolism takes place, producing a high number of oxygen radicals which leads to the destruction of foreign proteins. Some of these molecules can leak into the extracellular space during this process. This happens to a greater extent, when the leukocytes cannot encapsulate the foreign body because of its size or in cases where the neutrophils are destroyed (by bacterial toxins, crystalline substances etc.).
MPO, together with hydrogen peroxide and a halogen, forms a very strong anti microbial system, which can effectively combat a number of microorganisms. MPO is present at high concentration in neutrophil granulocytes, whereas hydrogen peroxide is produced during infection/ inflammation. The MPO system is inhibited by catalase, excess of hydrogen peroxide and other reducing substances (e.g. ascorbic acid, glutathione). In the absence of these agents other cells in the extracellular space can be affected (e.g. spermatocyte, erythrocytes, leukocytes, and tumor cells)
Apart from its implications in host defence, involvement of MPO has been described in numerous non-infectious diseases such as atherosclerosis, lung cancer, Alzheimer´s disease, and multiple sclerosis. MPO is present and active within atherosclerotic lesions. Numerous lines of evidence suggest mechanistic links between myeloperoxidase, inflammation and both acute and chronic manifestations of cardiovascular disease.
Brennan et al. (2003) showed that in 604 sequentially ascertained patients presenting with chest pain, a single initial measurement of plasma myeloperoxidase was an independent early predictor of myocardial infarction, as well as the risk of major adverse cardiac events in ensuing 30-day and 6-month periods. In contrast to troponin T, creatine kinase MB isoform, and C-reactive protein levels, MPO levels may identify patients at risk for cardiac events in the absence of myocardial necrosis.
PRINCIPLE OF THE TEST
Myeloperoxidase (MPO) ELISA Kit
The Myeloperoxidase (MPO) ELISA Kit is intended for the quantitative determination of MPO (Myeloperoxidase) in serum and plasma. The Myeloperoxidase (MPO) ELISA Kit assay utilizes the two-site “sandwich” technique with two selected polyclonal antibodies that bind to human MPO.
Assay standards, controls and prediluted patient samples containing human MPO are added to wells of microplate that was coated with a high affine polyclonal anti-human MPO antibody. After the first incubation period, antibody immobilized on the wall of microtiter wells captures human MPO in the sample. Then a peroxidase-conjugated polyclonal anti-human MPO antibody is added to each microtiter well and a “sandwich” of capture antibody - human MPO – Peroxidase conjugate is formed. Tetramethylbenzidine (TMB) is used as a substrate for peroxidase. Finally an acidic stop solution is added to terminate the reaction. The color changes from blue to yellow. The intensity of the yellow color is directly proportional to the concentration of MPO in the sample. A dose response curve of the absorbance unit (optical density, OD at 450 nm) vs. concentration is generated, using the values obtained from the standard. MPO present in the patient samples, is determined directly from this curve.
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