Generation and characterization of the human neutralizing antibody fragment Fab091 against rabies virus

Aim： To transform the human anti-rabies virus glycoprotein （anti-RABVG） single-chain variable fragment （scFv） into a Fab fragment and to analyze its immunological activity. Methods： The Fab gene was amplified using overlap PCR and inserted into the vector pComb3XSS. The recombinant vector was then transformed into E coil ToplOF＇ for expression and purification. The purified Fab was characterized using SDS-PAGE, Western blotting, indirect ELISA, competitive ELISA, and the fluorescent antibody virus neutralization test （FAVN）, respectively, and examined in a Kunming mouse challenge model in vivo. Results： A recombinant vector was constructed. The Fab was expressed in soluble form in E coil ToplOF＇. Specific binding of the Fab to rabies virus was confirmed by indirect ELISA and immunoprecipitation （IP）. The neutralizing antibody titer of Fab was 10.26 IU/mL. The mouse group treated with both vaccine and human rabies immunoglobulin （HRIG）/Fab091 （32 IU/kg） showed protection against rabies, compared with the control group （P〈0.05, Logrank test）. Conclusion： The antibody fragment Fab was shown to be a neutralizing antibody against RABVG. It can be used together with other monoclonal antibodies for post-exposure prophylaxis of rabies virus in future studies.