Description
Principle of the Assay::The Human CD21 ELISA (Enzyme-Linked Immunosorbent Assay) kit is an in vitro enzyme-linked immunosorbent assay for the quantitative measurement of Human CD21 in Cell Culture Supernatants, Serum, Plasma. This assay employs an antibody specific for Human CD21 coated on a 96-well plate. Standards and samples are pipetted into the wells and CD21 present in a sample is bound to the wells by the immobilized antibody. The wells are washed and biotinylated anti-Human CD21 antibody is added. After washing away unbound biotinylated antibody, HRP-conjugated streptavidin is pipetted to the wells. The wells are again washed, a TMB substrate solution is added to the wells and color develops in proportion to the amount of CD21 bound. The Stop Solution changes the color from blue to yellow, and the intensity of the color is measured at 450 nm.
Background/Introduction: Complement receptor type 2(CR2), also known as C3DR or CD21, is a protein that in humans is encoded by the CR2 gene. It is mapped to 1q32.2. CR2 is involved in the complement system. It binds to iC3b(inactive derivative of C3b), C3dg, or C3d. CR2 is the membrane protein on B lymphocytes to which the Epstein-Barr virus (EBV) binds during infection of these cells. CR2, together with CD19, CD81, and CD225, forms the B-cell coreceptor complex, which lowers the activation threshold of the B-cell antigen receptor. Genetic variations in this gene are associated with susceptibility to systemic lupus erythematosus type 9 (SLEB9)