Antigens

Patent Pending In immunology, an antigen (Ag), abbreviation of antibody generator, is any structural substance which serves as a target for the receptors of an adaptive immune response, TCR or BCR or its secreted form antibody, respectively.[1] Each antibody is specifically selected after binding to a certain antigen because of random somatic diversification in the antibody complementarity determining regions (a common analogy used to describe this is the fit between a lock and a key). Paul Ehrlich coined the term antibody (in German Antikörper) in his side-chain theory at the end of 19th century.