Antibodies are proteins produced by the body’s immune system when it detects harmful substances, called antigens. Examples of antigens include microorganisms (such as bacteria, fungi, parasites and viruses) and chemicals.
Antibodies can be produced when the immune system mistakenly regards healthy tissue as a harmful substance. This is called an autoimmune disorder. Each type of antibody is unique and defends the body against a specific type of antigen.
Each antibody can bind to only one specific antigen. The purpose of this binding is to help destroy the antigen. Some antibodies destroy antigens directly. Others make it easier for white blood cells to destroy the antigen. An antibody is a type of immunoglobulin.