Uses
Purified human IgM 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. IgM from human serum was used as standard in ELISA (100 μg/ml) and dot blot assay. Antibody concentration range of 200 μg/ml to 1 mg/ml was used in IgM binding assays.
IgM from human serum has been used
- in ELISA inhibition assay
- in immunoblotting
- as MW (molecular weight) standards
- in IgM binding assay
- to confirm the depletion of immunoglobulins
General Description
There are five immunoglobulin classes in humans. Out of these, immunoglobulin M (IgM) is a high molecular weight protein that has five or six subunits. IgM monomers are made of two heavy chains and two light chains connected by a disulfide bond. Human serum shows low concentration of IgM monomers. It has a high carbohydrate content of about 12%. It is the first immunoglobulin produced by neonates.
IgM antibodies are present as pentamers in the serum and are produced in response to antigens.
IgM from human serum is purified from normal human serum by precipitation and gel filtration techniques. The immunoglobulin is determined to be atleast 95% pure by HPLC procedures.
Biochem/physiol Actions
Immunoglobulin M (IgM) acts as an antigen specific part of the B cell antigen receptor on the surface of B lymphocytes that are not stimulated, in its monomeric form. Polymeric IgM molecules also serve as important activators of the classical complement cascade. IgM is essential in agglutination and cytolytic reactions.
