What is an Immunoglobulin?

An immunoglobulin is a glycoprotein molecule that is produced by plasma cells or white blood cells. Also known as antibodies, immunoglobulins make up about 20% of the protein in plasma. 

Immunoglobulins play an integral role in immune response. They have the ability to specifically recognize, bind to, and destroy specific antigens such as bacteria or viruses. 

There are five primary classes of immunoglobulins. The main difference between these five immunoglobulins is the type of heavy chain found in the molecule.  Each of these has its own distinct structure, features, distribution in the plasma and target specificity but all are equally important in the immune response to antigens. The different characteristics gives each immunoglobulin the ability to function in a different type of immune response and at a specific stage of the immune response.