VH-1-TCR Cα x VL-1-TCR Cβ; VH-2-CH-2-Fc x VL-2-CL-2: WuXiBody

WuXiBody, replace one parental mAb's CH1/CL region by the T cell receptor (TCR) constant domain. WuXiBody's design ensures cognate HC-LC pairing, the same goal as that being aimed by the CrossMab technology. BsAbs based on WuXiBody can adopt either asymmetric or symmetric format (Fig. 1). For asymmetric WuXiBody-based bsAbs, heterodimerization is promoted by the KiH technology. The TCR constant domain has a relatively low isoelectric point (pI) and consequently the target bsAb containing it also has a pI much lower than that of regular mAbs. In the case of asymmetric bsAbs, this feature promotes the use of ion exchange (IEX) chromatography to separate the target bsAb from potential non-TCR-containing byproducts (e.g., one type of half antibody and homodimer). Thus, introduction of TCR constant domain into WuXiBody construction not only promotes desired chain pairing but also facilitates removal of product-related impurities. Four WuXiBody-based bsAbs with different formats (two asymmetric and two symmetric ones) are show in Fig. 1.

Fig. 1. Schematic representation of four selected WuXiBody-based bsAbs (Adopted from: Guo, G., Han, J., Wang, Y., Li, Y. (2020) A potential downstream platform approach for WuXiBody-based IgG-like bispecific antibodies. Protein Expression and Purification. 173: 105647).

Formats of bispecific antibodies (BsAbs)

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