Hybridoma development involves the generation of cell lines that produce large numbers of a specific monoclonal antibody (mAb). The process involves immunization of an animal, usually a mouse, with a specific antigen to initiate an immune response and allow isolation of antibody-producing B cells. These are then fused with immortal myeloma cells to generate the hybridomas. The hybridomas are then screened, selected and the monoclonal population expanded. Hybridomas have a wide range of in vivo applications.