SEEDbodies: fusion proteins based on strand-exchange engineered domain (SEED) CH3 heterodimers in an Fc analogue platform for asymmetric binders or immunofusions and bispecific antibodies.

Bispecific antibodies and asymmetric Fc fusion proteins offer opportunities for important advances in therapeutics. Bivalent IgG depends upon in vivo dimerization of its heavy chains, mediated by homodimeric association of its C(H)3 domains. We have developed a heterodimeric Fc platform that supports the design of bispecific and asymmetric fusion proteins by devising strand-exchange engineered domain (SEED) C(H)3 heterodimers.