CD59 is a cell surface glycoprotein that regulates complement-mediated cell lysis, and it is involved in lymphocyte signal transduction. Complement activation ultimately leads to formation of the cytotoxic, poreforming membrane attack complex (MAC), the main effector of complement-mediated tissue damage. Insertion of the MAC into cell membranes induces the release of cytokines and growth factors that promote inflammation, thrombosis, and cell proliferation. CD59 is a complement regulatory protein ubiquitously expressed on mammalian cell surfaces and it specifically inhibits MAC formation and thereby protects “self” cells from complement-mediated damage. The protein also plays a role in signal transduction pathways in the activation of T cells. Mutations in the CD59 gene cause CD59 deficiency, a disease resulting in hemolytic anemia and thrombosis, and which causes cerebral infarction. CD59 was demonstrated to be present in plasma/serum of healthy individuals in levels ranging from 22 to 119 ng/ml.
The sCD59 ELISA kit is to be used for the in vitro quantitative determination of human sCD59 in plasma.
The sCD59 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 microtiter wells coated with antibodies recognizing human sCD59. Biotinylated tracer antibody will bind to the captured human sCD59. 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 sCD59 standards (log). The human sCD59 concentration of samples, which are run concurrently with the standards, can be determined from the standard curve.