Antigen and Antibody

Antigen is a substance that is capable of stimulating an immune response. These are the commercial substance which are injected or absorbed into animal tissues to stimulates the production of antibodies. It is capable of binding to an antibody or to an antigen receptor on a T cell. Antigen helps in the production of antibodies. The antigen may originate from within the body ("self-antigen") or from the external environment ("non-self").