Expression of influenza virus nonstructural protein 1 (NS1)

Avian influenza poses a threat to many species including man, as shown by the current scenario in Southeast Asia. It appears that this particular type of influenza virus can spread to many species causing severe disease in these new species. For example, from 258 human cases 154 were fatal (WHO, 2006-11-29). Why some avian influenza virus have the ability to infect other species remains to be understood. One viral gene, coding for the non-structural protein 1 (NS1), appears to be an important factor for successfully transmission into a new host, by counteracting the new host’s immune system. The exact mechanism of action of NS1 is still unclear, but leads to down-regulation of various pathways of the immune defence. The aim of this study was to express NS1 proteins of influenza viruses originating from different hosts, including highly pathogenic avian influenza viruses, for use in investigations on the mechanism used by NS1 to interfere with the immune system of various hosts. In particular, studies on the interaction of NS1 with the RNA dependent protein kinase (PKR) were initiated, to determine differences in this interaction between high and low pathogenic influenza viruses from different hosts. By establishing tools and optimised assays, the work enables further studies on the role NS1 in immune evasion.