Introduction Human immunoglobulin G (IgG), the most abundant antibody in the serum, constitutes 75% of serum immunoglobulins. IgG is synthesized and secreted by plasma B cells and contains two heavy chains and two light chains. IgG has four subclasses IgG1, IgG2, IgG3, and IgG4 and is involved in the secondary immune response. As it is the only isotype that can pass through the human placenta, maternal IgG provides the defense against infection for the first few weeks of a neonate (1). IgG has been shown to treat autoimmune disease, induce apoptosis, and attenuate complement (3 - 4). Elevated IgG is observed in viral hepatitis, autoimmune hepatitis, and cirrhosis (5).
Principle of the Assay The AssayMax Human IgG3 ELISA (Enzyme-Linked Immunosorbent Assay) kit is designed for detection of human IgG3 in plasma, serum, urine, saliva, milk, and cell culture supernatants. This assay employs a quantitative sandwich enzyme immunoassay technique that measures human IgG3 in less than 4 hours. A polyclonal antibody specific for human IgG3 has been pre-coated onto a 96-well microplate with removable strips. IgG3 in standards and samples is sandwiched by the immobilized antibody and the biotinylated polyclonal antibody specific for IgG3, which is recognized by a streptavidin-peroxidase conjugate. All unbound material is then washed away and a peroxidase enzyme substrate is added. The color development is stopped and the intensity of the color is measured.