Bispecific monoclonal antibodies (bsMAb) are proteins capable of binding to two
different antigen-binding sites in one molecule. By simultaneous recognition of two different targets, bispecific antibodies can inhibit two signaling pathways by targeting two different receptors on the same cell or by targeting two different ligands simultaneously using two physically connected paratopes. Currently, two major classes of bispecific antibodies are widely studied: IgG-like bispecific antibodies and non-IgG-like bispecific monoclonal antibodies. IgG-like antibodies are structurally equal to natural IgG molecules; however, they cannot be synthesized by natural B lymphocytes. This means that resources are mainly put into developing cell lines that can synthesize them. Non-IgG-like bispecific antibodies do not contain a Fc-portion and are made up from a single polypeptide chain – this eases upstream and downstream processing. Bispecific antibodies can be difficult to produce in high-scale production. The synthesis of these molecules requires extensive protein-engineering and development of the manufacturing process. Bispecific antibodies might improve treatment options against cancer, autoimmune diseases, and inflammatory diseases. Although some methods have proven great success in synthesizing a safe and powerful molecule, it’s important to simplify the structure and production procedure so next generations of these molecules can be more widely used.
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