Immunoglobulin are glycoproteins that function as antibodies. The terms immunoglobulin and antibody are often used interchangeably. They are found in the blood, tissue fluids, and many secretions. Stucturally, immunoglobulins are considered globulins. They are synthesized and secreted by the B cells of the immune system.
Immunoglobulins are heavy plasma proteins, often with added sugar chains. According to differences in their heavy chain constant domains, immunoglobulins are grouped into five classes or isotypes: IgG, IgA, IgM, IgD, and IgE. These antibodies work to protect the immune system - they identify and neutralize foreign object like bacteria and viruses. Each antibody recognizes a specific antigen unique to its target.
Immuoglobulins are crucial to a healthy body.