Multichain Trimerbody (MTs) made by fusing the target antigen-binding domain/s [single-chain fragment variable (scFv), single-domain antibody (sdAb) or antibody mimetic] to the N- and/or C-terminus of a collagen TrImErization (TIE) domain flanked by short flexible linkers (Figure 1). Due to their multivalence, MTs demonstrated specific antigen binding, increased avidity, slow off-rates in vitro and improved tumor-targeting efficacy in vivo in several mouse models of cancer. Additionally, these molecules are efficiently produced as soluble functional proteins by standard manufacturing methods including bacteria (E. coli), yeast (P. pastoris), insect and mammalian cells (CHO, 293, etc).
The TT strategy allows the efficient generation of multispecific molecules from pre-existent single-domain antibodies. As this new format targets up to three antigens per molecule it might have therapeutic potential and conceivable diagnostic or imaging use in many diseases, as simultaneously inhibiting different pathways involved in pathogenesis can prevent resistance from being established.