Journal of Antivirals & Antiretrovirals
Open Access

Annual seasonal infl uenza vaccination and crossneutralization to the pandemic 2009 H1N1 infl uenza virus

International Conference and Exhibition on VIROLOGY

5-7 September 2011 Baltimore, USA

Wei Wang

Keynote: JAA

Abstract :

Annual seasonal infl uenza vaccination (TIV) induces the production of neutralizing antibody to the hemagglutinin (HA) surface protein. Mutations that change antigencity occur predominantly in the globular head (HA1 subunit) of HA, while the stem region of the HA transmembrane subunit (HA2) is more conserved. Pandemic 2009 H1N1 infl uenza virus diff ers from seasonal H1N1 strains that circulated in the past 50 years and resembles a strain that did not circulate but was used in the 1976 swine infl uenza vaccine. Emergence of the novel pandemic infl uenza A virus (pdm2009 H1N1) raised questions about whether immunization with prior infl uenza vaccines could confer any protection. We investigated whether persons immunized with the 1976 swine fl u or recent seasonal infl uenza vaccines, or both, harbor neutralizing antibodies to pdm2009 H1N1. We found that archived sera from the 1976 swine infl uenza vaccine trials cross-neutralized the pdm2009 H1N1 and to a lesser extent the A/New Caledonia/20/1999 H1N1 strain, which was used in vaccines during the 2000/01-2006/07 infl uenza seasons. Sera from persons who received several seasonal infl uenza vaccines containing A/New Caledonia/20/1999 H1N1 cross-neutralized the pdm2009 H1N1, regardless of whether they received the 1976 swine infl uenza vaccine. Cross-neutralization between pdm2009 H1N1 and A/New Caledonia/20/1999 frequently mapped to HA2. A conservative mutation in HA2 corresponding to a residue at 89 in the A/Solomon Islands/3/2006 and A/Brisbane/59/2007 H1N1 strains that circulated in the 2006/07 and 2007/08 infl uenza seasons, respectively, abrogated this neutralization. Th ese fi ndings highlight a cross-neutralization determinant infl uenced by a point mutation in HA2 and suggest that HA2 may be evolving under direct or indirect immune pressure.

Biography :

Dr. Wei Wang received his Ph.D. in 2000 from the University of Saskatchewan, Canada, and completed postdoctoral studies from National Cancer Institute. He joined US Food and Drug Administration in 2005.