Several methods have been developed to produce mouse antibodies up to now. Initially, mouse antibodies are usually obtained by hybridoma technique, which is developed by fusing immortal mouse myeloma cells and splenic B cells from immunized animals. Due to the rapid growth in demand for antibody production and serious animal welfare concerns, recombinant technology has gradually replaced the hybridoma technique recently. The recombinant antibodies can be produced without the use of animals.