Creative Biolabs collects hot therapeutic targets and provides a variety of customized bispecific antibody (BsAb) products. Based on the advanced strategies and to fit the desired the target-product profile, we can help develop different formats of BsAbs adapted the valency, structure, half-life and biodistribution, etc.
Tandem scFvs are a class of bispecific antibody fragments. Two or more moieties of scFv string together to form tandem scFv, which has 1+1 (+1…) antigen-binding valency.
Tandem Fab is bispecific and has monovalent specificity for each antigen (1+1 antigen-binding valency).
Diabody is a dimer of scFv. Bispecific Diabody has monovalent specificity for each antigen (1+1 antigen-binding valency).
IgG-scFv is a type of appended IgGs. It is bispecifc and can be 2+2, 2+1+1, 1+1+1+1 antigen-binding valency.
CrossMab is a type of IgG-like bispecific antibody. Similarly to conventional IgG, CrossMab is bispecific and bivalent molecule, 1+1 antigen-binding valency.
IgG-IgG conjugates are formed by chemical linkage. Parental antibodies with special tags can be conjugated in 1:1 to form dimers.
Triple Body (also known as Tribody, not the scFv triple-body) is a multifunctional rAb derivative, combination of Fab with additional entities.
Fab-IgG (also tandem Fab-Fc in the construct) is a format of appended IgGs, the IgG scaffold with Fab fragment in the N terminus. They are symmetric bispecific and tetravalent molecules, 2+2 antigen-binding valency.
TandAb (Tandem diabody) is a tetravalent bispecific molecule, 2+2 antigen-binding valency, consisting solely of Fv domains. They have been studied as BiTEs or BiKEs in tumor immunotherapy.
Single-chain Diabody (scDb) is a derivative of Diabody. scDb connects the first chain and the second chain of diabodies by a flexible linker, transforming the heterodimeric format of diabody into a single-chain format.
Single-chain triplebody (Sctb) can be regarded as tandem scFv in terms of the structure. It has three tandem scFv units, bispecific or trispecific, 2+1 or 1+1+1 antigen-binding valency.
Fab-Fv is a bispecific, bivalent (1+1) fragment. It is generated by a VH domain fusing to the C-terminal of a Fd fragment and a VL domain to a light chain.
Minibody is a bispecific, bivalent (1+1) fusion molecules. It is constructed by two scFvs fused to the CH3 domains respectively. The KIH CH3 serves as heterodimerization domain.
Bispecific immunotoxins (BITs) are hybrid molecules with two specific targeting ligands fused to a toxin moiety. The toxins reach specific diseased tissue guided by the bispecific targeting molecules and perform the cytotoxic effects.
scFv-based Bispecific Fragments
Scfv fragments are a class of units that are commonly used to generate BsAbs. Beside the formats widely studied, there are numerous other scFv-based bispecific fragments.
Bibody is a Fab-scFv fusion protein which utilizes Fab as the scaffold and scFv is incorporated to the C-terminus of Fd or light chain. It is a bispecific, bivalent molecule.
Monospecific IgGs can be engineered by fusing additional antigen-binding units such as scFv, Fab, protein scaffolds, etc.
Fab-scFv Fusion Proteins
Fab and scFv are two main binding units to generate bispecific antibodies. There is a class of BsAbs comprising both Fab and scFv.