[Generation of neutralizing recombinant human antibodies for targeting highly pathogenic avian influenza A (H5N1)
Li-Na Sun1, Qin-Zhi Liu, Min Wang
1State Key Laboratory for Infectious Disease Control and Prevention, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China.
Abstract:
Two human Fab antibodies against avian influenza A (H5N1) virus were obtained by panning a H5N1 patient-derived antibody phage library using purified virions of the H5N1 patient isolate A/Anhui/1/2005 and HA protein of the H5N1 reference viruse A/Viet Nam/1203/2004. After testing the binding properties and antiviral function to H5N1 virus, the selected Fab antibodies were converted to full human IgG antibodies with recombinant baculovirus/insect cell system. Both mAbs, AVFluIgG01 and AVFluIgG03, bound to HA in immunofluorescence assay (IFA) without cross-reaction with the other substypes of influenza A viruses (H1N1, H3N2). The cross-reactivity of the two antibodies for different strains of H5N1 was tested in vitro by micro-neutralization assays. In vitro, mAb AVFluIgG01 potently neutralized not only the selected well-characterized Clade 2 H5N1 viruses isolated from mainland of China except A/Guangdong/1/2006, but also the Clade 1 representative isolate A/Viet Nam/1203/2004; and AVFluIgG03 neutralized all the selected Clade 2 H5N1 viruses isolated from mainland of China, but had no neutralizing activity with the Clade 1 H5N1 virus A/Viet Nam/1203/2004. The results bring new prospect for the prophylaxis or treatment of H5N1 virus infection and may provide a clue for novel vaccine development.
