Immunoglobulins

Immunoglobulins or antibodies, are proteins produced by B cell derived plasma cells. They play an important role in the immune system, and possess the ability to bind to specific antigens, facilitating the destruction of potential pathogens, usually via the activation of complement.

• five different types (known as isotypes) of antibody in the human immune system - namely IgM, IgG, IgA, IgE and IgD
  • in addition, there are four sub classes of IgG (IgG1-4)
• basic antibody unit consists of a glycosylated protein consisting of two heavy and two light, polypeptide chains
  • region which binds to the antigen is known as the Fab region
  • the constant region, Fc, not only determines the isotype but is the region responsible for evoking effector systems, e.g. mast cell activation
  • " immune complex" refers to the combination of antigen and antibody

However, immunoglobulins also may play a role in the pathogenesis of certain autoimmune conditions, myeloma and immune-complex diseases.