Progress in Single-domain Antibody Derived from Heavy chain Antibody
基于重链抗体构建的单域抗体研究进展

Functional heavy-chain antibodies (HCAbs) lacking light chains occur naturally in camels. The variable domain of heavy chain of heavy-chain antibody is referred to VHH. The VHH gene family is homologous to human VH subgroup III. The single-domain VHH antibodies are constructed by cloning the variable domains of HCAbs. Compared to human VHs, VHH germ-line sequences contain some hallmark substitutions in framework region 2, including V37F(Y), G44 E, L45 R, W47G. The substitutions at positions 44, 45, 47 are often used to camelise the human VHs. Being a small binders, VHH antibodies are well expressed, extremely stable and very soluble. Camelised human VHs are proved to exhibit the same qualities as those of VHH antibodies. The single-domain VHH antibodies will be useful in the drug development and basic research.