Description
Intended Uses: This is a solid phase enzyme immunoassay with highly purified human phosphatidyl-serine plus native human prothrombin for the detection of IgA antibodies against phosphatidyl-serine and prothrombin in human serum.
Principle of the Assay: Serum samples diluted 1:101 are incubated in the microplates coated with the specific antigen. The antibodies, if present in the specimen, bind to the antigen. The unbound fraction is washed off in the following step. Afterwards anti-human immunoglobulins conjugated to horseradish peroxidase (conjugate) are incubated and react with the antigen-antibody complex of the samples in the microplates. Unbound conjugate is washed off in the following step. Addition of TMB-substrate generates an enzymatic colorimetric (blue) reaction, which is stopped by diluted acid (color changes to yellow). The intensity of color formation from the chromogen is a function of the amount of conjugate bound to the antigen-antibody complex and this is proportional to the initial concentration of the respective antibodies in the sample.
Background: Antibodies against prothrombin and phosphatidyl-serine, an acidic phospholipid derived from glycerol, belong to the group of anti-phospholipid antibodies specific for phospholipids such as cardiolipin, phosphatidyl- inositol, -ethanolamin, -choline, sphingomyelin, phosphatidic acid and prothrombin. Phospholipids are components of biological membranes. Prothrombin (human factor II) is a plasme zymogen with a molecular weight of 72 kDa. It assembles with the activated forms of Factor V, Factor X and phospholipid to form a catalytic unit known as the prothrombinase complex. In the presence of calcium ions, the complex cleaves the membrane-associated prothrombin into thrombin, which is then released into the soluble phase