A novel variable antibody fragment dimerized by leucine zippers with enhanced neutralizing potency against rabies virus G protein compared to its corresponding single-chain variable antibody fragment

作者：Li, Zhuang; Cheng, Yue; Xi, Hualong; Gu, Tiejun; Yuan, Ruosen; Chen, Xiaoxu; Jiang, Chunlai; Kong, Wei^*; Wu, Yongge

来源：Molecular Immunology, 2015, 68(2): 168-175.

DOI：10.1016/j.molimm.2015.06.027

• Rabies virus
• Leucine zipper
• Single chain variable fragment
• Zip variable fragment
• Glycoprotein
• Virus-neutralization antibody

Fatal rabies can be prevented effectively by post-exposure prophylactic (PEP) with rabies immunoglobulin (RIG). Single-chain variable fragments (scFv), which are composed of a variable heavy chain (V-H) and a variable light chain (VL) connected by a peptide linker, can potentially be used to replace RIG. However, in our previous study, a scFv (scFV57S) specific for the rabies virus (RV) G protein showed a lower neutralizing potency than that of its parent IgG due to lower stability and altered peptide assembly pattern. In monoclonal antibodies, the V-H and V-L interact non-covalently, while in scFvs the V-H is connected covalently with the V-L by the artificial linker. In this study, we constructed and expressed two peptides 57V(L)-JUN-HIS and 57V(H)-FOS-HA in Escherichia coli. The well-known Fos and Jun leucine zippers were utilized to dimerize V-H and V-L similarly to the IgG counterpart. The two peptides assembled to form zipFv57S in vitro. Due to the greater similarity in structure with IgG, the zipFv57S protein showed a higher binding ability and affinity resulting in notable improvement of in vitro neutralizing activity over its corresponding scFv. The zipFv57S protein was also found to be more stable and showed similar protective rate as RIG in mice challenged with a lethal dose of RV. Our results not only indicated zipFv57S as an ideal alternative for RIG in PEP but also offered a novel and efficient hetero-dimerization pattern of V-H and V-L leading to enhanced neutralizing potency.

• 出版日期2015-12
• 单位吉林大学