Bispecific antibody derivatives based on full-length IgG formats.

Monoclonal antibodies have emerged as an effective therapeutic modality, and numerous antibodies have been approved for the treatment of several severe diseases or are currently in clinical development. To improve their therapeutic potential, monoclonal antibodies are constantly evolved by protein engineering. Particularly, the generation of bispecific antibodies raised special interest because of their ability to bind two different antigens at the same time, and the efficiency of these formats has been demonstrated in several clinical and preclinical studies. Up to now, the major drawbacks in using bispecific antibodies as a therapeutic agent have been difficult design and low-yield expression of homogeneous antibody populations. However, major technological improvements were made in protein engineering during the last years. This allows the design of several new IgG-based bispecific antibody formats that can be prepared in high yields and high homogeneity using conventional expression and purification techniques. Especially, recent development of IgG-fusions with disulfide-stabilized Fv fragments and of CrossMab-technologies facilitates the generation of bispecific antibodies with IgG-like architectures. Here we describe design principles and methods to express and purify different bispecific antibody formats derived from full-length IgGs.