NS1 proteins of avian influenza A viruses can act as antagonists of the human alpha/beta interferon response

Hayman, A., Comely, S., Lackenby, A., Hartgroves, L. C. S., Goodbourn, S., McCauley, J. W. and Barclay, W. S. (2007) NS1 proteins of avian influenza A viruses can act as antagonists of the human alpha/beta interferon response. Journal of Virology, 81 (5). pp. 2318-2327. ISSN 0022-538X doi: 10.1128/jvi.01856-06

Abstract/Summary

Many viruses, including human influenza A virus, have developed strategies for counteracting the host type I interferon (IFN) response. We have explored whether avian influenza viruses were less capable of combating the type I IFN response in mammalian cells, as this might be a determinant of host range restriction. A panel of avian influenza viruses isolated between 1927 and 1997 was assembled. The selected viruses showed variation in their ability to activate the expression of a reporter gene under the control of the IFN-beta promoter and in the levels of IFN induced in mammalian cells. Surprisingly, the avian NS1 proteins expressed alone or in the genetic background of a human influenza virus controlled IFN-beta induction in a manner similar to the NS1 protein of human strains. There was no direct correlation between the IFN-beta induction and replication of avian influenza viruses in human A549 cells. Nevertheless, human cells deficient in the type I IFN system showed enhanced replication of the avian viruses studied, implying that the human type I IFN response limits avian influenza viruses and can contribute to host range restriction.