[Generation of Human ScFv Antibodies for Antigenic Site III of Rabies Virus Glycoprotein from Antibody-phage Libraries by Chain Shuffling].

Abstract

To obtain neutralizing high affinity human recombinant antibodies for antigenic site Ⅲ of rabies virus(RV)glycoprotein, we chose scFv phage display technology to optimize CR4098 with chain shuffling. Using pHAL14-CR4098 as vector, the combinatorial shuffling scFv antibody phage libraries were constructed to replace CR4098 light or heavy chain genes respectively by antibody genes derived from the blood of RV-vaccinated donors. After package by hyperphage, the chain shuffling scFv phage library was panned and selected by ELISA with purified rabies virus aG strain. The specific antibody was converted to full human IgG antibody with the VH/VK Express cassettes. Affinity and neutralizing test were performed to verify the function of the IgG molecules. Fourteen unique human ScFv antibodies specific for the glycoprotein of rabies virus were obtained by ELISA,IFA and DNA sequencing. Further tested showed that RV3A5 has a high affinity of 2.8×10(-9) M and high neutralizing activity to rabies virus both aG strains and CVS strains. Competitive ELISA showed that RV3A5 and CR4098for antigenic Site III competed with each other, indicating that they had overlapping or shared the epitope. Our results provide more candidates eligible for use in a mAb cocktail aimed at replacing RIG for rabies post-exposure prophylaxis.