classes of immunoglobulin

Last reviewed 01/2018

There are five main classes of immunoglobulin; IgA, IgE, IgG, IgM and IgD.

The basic component of each of these classes is a "Y" shaped monomer, formed of two heavy chains and two light chains. There are variable and constant regions of both heavy and light chains. Variable regions form the antigen - binding sites. The types of light chains in immunoglobulins are common to all classes (these are termed kappa and lambda). The heavy chains are class-specific.

The basic unit of immunoglobulins - the monomer - has a molecular weight of about 150 kilodaltons.