Measurement of neutralizing antibody responses against H5N1 clades in immunized mice and ferrets using pseudotypes expressing influenza hemagglutinin and neuraminidase.

Cheguo Tsai (1) , Catherine Caillet (2) , Hongxing Hu (1) , Fan Zhou (1) , Heng Ding (1) , Guoliang Zhang (3) , Boping Zhou (3) , Shixia Wang (4, 5) , Shan Lu (4, 5) , Philippe Buchy (6) , Vincent Deubel (1) , Frederick R Vogel (2) , Paul Zhou (1)

1 IPS-CAS - Institut Pasteur de Shanghai, Académie des Sciences de Chine - Chinese Academy of Sciences
2 Sanofi Pasteur [Marcy-l'Étoile, France]
3 Donghu Hospital
4 Laboratory of Nucleic Acid Vaccine, Department of Medicine, University of Massachusetts Medical School
5 China-US Vaccine Research Center, 1st Affiliated Hospital, Nanjing Medical University
6 Institut Pasteur du Cambodge

Neutralizing antibody is associated with the prevention and clearance of influenza virus infection. Microneutralization (MN) and hemagglutination inhibition (HI) assays are currently used to evaluate neutralizing antibody responses against human and avian influenza viruses, including H5N1. The MN assay is somewhat labor intensive, while HI is a surrogate for neutralization. Moreover, use of replication competent viruses in these assays requires biosafety level 3 (BSL-3) containment. Therefore, a neutralization assay that does not require BSL-3 facilities would be advantageous. Toward this goal, we generated a panel of pseudotypes expressing influenza hemagglutinin (HA) and neuraminidase (NA) and developed a pseudotype-based neutralization (PN) assay. Here we demonstrate that HA/NA pseudotypes mimic release and entry of influenza virus and that the PN assay exhibits good specificity and reveals quantitative difference in neutralizing antibody titers against different H5N1 clades and subclades. Using immune ferret sera, we demonstrated excellent correlation between the PN, MN, and HI assays. Thus, we conclude that the PN assay is a sensitive and quantifiable method to measure neutralizing antibodies against diverse clades and subclades of H5N1 influenza virus.

Domains: Microbiology and Parasitology

Cheguo Tsai, Catherine Caillet, Hongxing Hu, Fan Zhou, Heng Ding, et al.. Measurement of neutralizing antibody responses against H5N1 clades in immunized mice and ferrets using pseudotypes expressing influenza hemagglutinin and neuraminidase.. Vaccine, 2009, 27 (48), pp.6777-90. ⟨10.1016/j.vaccine.2009.08.056⟩. ⟨pasteur-00625272⟩