HUMAN IGG

Purified human IgG may be used as a reference antigen, standard, blocking agent, or coating protein in a variety of immunoassays including ELISA, dot immunobinding, Western immunoblotting, immunodiffusion, and immunoelectrophoresis. Other applications include starting materials for the preparation of immunogens and solid phase immunoadsorbents. Technical grade human IgG may be used as an economical alternative to the reagent grade immunoglobulins, in applications where high purity is not required. IgG from human serum was used as ELISA standard in various studies. A concentration range of 200 μg/ml to 1 mg/ml of human IgG was used for blocking in flow cytometry.

IgG antibody subtype is the most abundant serum immunoglobulins of the immune system. It is secreted by B cells and is found in blood and extracellular fluids and provides protection from infections caused by bacteria, fungi and viruses. Maternal IgG is transferred to fetus through the placenta that is vital for immune defence of the neonate against infections
Human IgG is purified from normal human serum by precipitation and gel filtration techniques.

IgG (Fc=γ) participates in precipitation reactions,toxin neutralizations, and complement fixation. IgG isthe major (70%) human Ig. The Fab tip fixes antigen, andthe Fc fragment can fix complement to yield agglutinationor lysis. IgG is the only immunoglobulin that crosses thetransplacental barrier and the neonatal stomach, so it providesmaternal protection. IgG constitutes about 75% of thetotal Ab in the circulation. It is present at a concentration ofabout 15 mg/mL and has a half-life of 3 weeks, the longestof any of the Ab types. The light chains of IgG can possesseither κ or λ variants. These slight differences in structureare called isotypes, and the phenomenon is termed isotypicvariation.