Format of bispecific antibodies (BsAbs)-Hetero H, forced HL IgG1


Hetero H, forced HL IgG1/ DuetMab replaces the native disulfide bond in the CH1-CL interface with an engineered disulfide bond (fig. 1). This enhances cognate light chain pairing. Three different positions in the CH1-CL interface are possible candidates for favoring the formation of a novel disulfide bond. An amino acid on the HC and one on the LC is replaced with cysteine in one of the Fab regions. The native disulfide bond on the other Fab region is left intact. It is advantageous that the modifications are in the CH1-CL interface and not in the variable domain, as this could have detrimental effects on antigen binding. Although, engineering in the CH1-CL interface could mean that κ and λ constant light chains would somehow affect the usefulness of this approach. However, it was shown to be compatible to both isotypes (Mazor et al. 2015). DuetMab could be generically applied to bispecific antibodies in development since the approach: (i) does not contain variable domain engineering, (ii) is compatible with both kappa and lambda isotypes and (iii) was able to induce correct heterodimerization.

Fig. 1. Schematic diagram to differentiate conventional monospecific mAbs (antibodies A and B) from DuetMab. The DuetMab is comprised of one wild-type Fab and one engineered Fab with the interchain disulfide redesigned (in red) within the CH1-CL interface. The yellow star on the hole heavy chain represents the RF mutation to ablate protein A binding. (Adopted from: Mazor, Y., Oganesyan, V., Yang, C., Hansen, A., Wang, J., Liu, H., Sachsenmeier, K., Carlson, M., Gadre, D.V., Borrok, M.J., Yu, X.Q., Dall'Acqua, W., Wu, H., Chowdhury, P.S. (2015) Improving target cell specificity using a novel monovalent bispecific IgG design. MAbs. 7(2):377-89.)

Formats of bispecific antibodies (BsAbs)

Many formats have been developed for BsAb generation as listed in the following table.

FormatSchematic structureDescriptionExample BsAbTrademark Company
tandem VHHTandem VHH fragment-based BsAbN/A
tandem scFvPicture loading failed.Tandem ScFv fragment-based BsAbAMG330BiTETMAmgen
Dual-affinity re-targeting antibodyPicture loading failed.Tandem domain-exchanged Fv (can also be used to fuse with Fc domain to create whole Abs)FlotetuzumabDARTTMMacrogenics
DiabodyPicture loading failed.dimer of single-chain Fv (scFv) fragmentvixtimotamabReSTORETMAmphivena Therapeutics
(scFv)2-FabPicture loading failed.a Fab domain and two scFv domains bindA-337ITabTMGeneron/EVIVE Biotech
Rat–mouse hybrid IgGPicture loading failed.Full-size IgG-like half antibodies from two different speciesCatumaxomabTriomabTMTrion Pharma
Hetero heavy chain, Common light chainPicture loading failed.Hetero heavy chain, Common light chainEmicizumabART-IgTMGenentech/ Chugai/Roche
Controlled Fab arm exchangePicture loading failed.Recombin the parental half antibodies JNJ-64007957DuobodyTMGenmab/ Janssen
Hetero H, forced HL IgG1Picture loading failed.KIH technology for heterodimerization of 2 distinct H chains, replacing the native disulfide bond in one of the CH1-CL interfaces with an engineered disulfide bond to enhance the cognate of H and L paringMEDI5752DuetMabTMMedImmune/ AstraZeneca
cH IgG1Picture loading failed.Identical heavy chains; 2 different light chains: one kappa (κ) and one lambda (λ)NI-1701κλ bodyTMNovimmune SA
Hetero H, CrossMabPicture loading failed.KIH technology; domain crossover of immunoglobulin domains in the Fab regionVanucizumabCrossMabTMRoche
scFv-Fab IgGPicture loading failed.Fab-Fc; ScFv-FcVibecotamab;
XmabTM (the engineered Fc to enhance the generation of heterodimeric Fc);
Xencor/Amgen; YZYBio
VH1-VH2-CH1-Fc1(G1) x VL2-VL1-CL-Fc2(G1)Picture loading failed.2 binding motif in one half antibodySAR440234CODV-IgTMSanofi
VL1-CL1-VH2-CH2-Fc x VH1-CH1 x VL2-CL2Picture loading failed.2 binding motif in one half antibodyEMB-01FIT-IgTMEPIMAB BIOTHERAPEUTICS
VH-1-TCR Cα x VL-1-TCR Cβ; VH-2-CH-2-Fc x VL-2-CL-2Picture loading failed.KIH technology; TCR Cα/Cβ is used to substitute the CH1 and CL domain in one armWuXibodyTMWuXi Biologics
C-terminal linker of FcPicture loading failed.Link the other molecules at the C-terminal of FcAPVO442ADAPTIR-FLEXTMAptevo Therapeutics
Fc antigen binding sitePicture loading failed.2 natural binding sites; 2 additional binding sites in the Fc loopFS118mAb2F-star Therapeutics