Antibody

Antibodies (also known as immunoglobulins) are gamma globulin proteins that are found in blood or other bodily fluids, and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses. They are typically made of basic structural units - each with two large heavy chains and two small light chains - to form, for example, monomers with one unit, dimers with two units or pentamers with five units. Antibodies are produced by a kind of white blood cell called a B cell. There are several different types of antibody heavy chain, and several different kinds of antibodies, which are grouped into different isotypes based on which heavy chain they possess. The 5 antibody isotypes known as IgA, IgD, IgE,IgG and IgM. They are each named with an "Ig" prefix that stands for immunoglobulin, and differ in their biological properties, functional locations and ability to deal with different antigens.