Title

Altered pathogenicity for seasonal influenza virus by single reassortment of the RNP genes derived from the 2009 pandemic influenza virus

ORCiD

David M. Ojcius: 0000-0003-1461-4495

Document Type

Article

Publication Title

Journal of Infectious Diseases

ISSN

0022-1899

Volume

204

Issue

6

DOI

10.1093/infdis/jir435

First Page

864

Last Page

872

Publication Date

9-15-2011

Abstract

Background. The 2009 influenza A pandemic virus (H1N1pdm) may reassort with old seasonal influenza A virus (H1N1141) in humans and potentially change their pathogenicity.

Methods and Results. This study focuses on the reassortment of ribonucleoproteins (RNPs) among H1N1pdm and seasonal influenza A viruses. A single RNP gene reassortment altered reporter gene expression levels driven by polymerase complex in transfection system. The growth rates of recombinant viruses with different RNP recombinations were changed in A549 cells. Mice were infected with recombinant viruses containing single RNP gene reassortment, and pathogenicity was examined. The results demonstrated that the median lethal dose (LD50) of the PB2141/PB1141/PApdm/NP141 recombinant virus was lower than that of the seasonal H1N1 virus. Viral titers of this reassorted virus in the lung and spleen were significantly higher than that in seasonal H1N1 virus-challenged mice.

Conclusions. Although the changes of RNP activity did not exactly reflect to mice virulence, we consistently observed that the PA gene of H1N1pdm results in increased polymerase activity, better replication in mice, and lower LD50. Our findings suggest that monitoring of gene reassortment for the 2009 pandemic influenza and seasonal human viruses is also important, which would help to constrain the potential emergence of a more virulent influenza A variant.