Since the first hybridoma has been obtained, a kind of possibility has arisen to modify the antibody to enhance its functionality. During this decade, antibody has become a major class of new drugs to treat several disease indications including cancer and autoimmune diseases. As the foundation of many diagnostics and therapeutics, the specific antigen binding ability of antibodies is critical for variety purposes, such as expanding detection limits, extending dissociation half-life time, decreasing therapeutic dosages and increasing overall efficacy. Nevertheless, it is still beneficial to optimize these antibodies or antibody related molecules with respect to their activity.

Through modern molecular biology techniques, interested antibodies can be specific modified or engineered to suit the application. If the heavy- and light-chain sequences are determined, the interested antibody can be reconfigured into different isotypes or a variety of formats (scFv, Fab, sdAb, bispecific antibody, etc.) and other possible modification including affinity measurement, humanization, caninization and so on. One feasible way is done by sequencing and cloning the interested region of antibody and grafting this select region onto a suitable framework to construct a plasmid.