Detection of Extensive Cross-Neutralization between Pandemic and Seasonal A/H1N1 Influenza Viruses Using a Pseudotype Neutralization Assay

摘要: Background Cross-immunity between seasonal and pandemic A/H1N1 influenza viruses remains uncertain. In particular, the extent that previous infection or vaccination by can elicit protective immunity against is unclear. Methodology/principal findings Neutralizing titers (A/Brisbane/59/2007) (A/California/04/2009) were measured using an HIV-1-based pseudovirus neutralization assay. Using this highly sensitive assay, we found a large fraction of subjects who had never been exposed to express high levels neutralizing titers. A significant correlation was seen standard strain. Significantly higher in received 2008-2009. Higher also over 60 years age. Conclusions/significance Our reveal cross-immunity may be more important than previously estimated. This could provide possible explanation relatively mild profile recent pandemic.