A bispecific monoclonal antibody (BsMAb, BsAb) is an artificial protein that it’s composed of fragments of two different monoclonal antibodies and consequently binds to two different types of antigen. The most widely used application of this approach is in cancer immunotherapy, where BsMAbs are engineered that simultaneously binds to a cytotoxic cell (using a receptor like CD3) and a target like a tumour cell to be destroyed. Fig. 1 below presents three types of bispecific antibodies, trifunctional antibody, chemically linked Fabs’ and bispecific T cell engager (BiTE). Parts of the two different antibodies are coloured blue and green, respectively.