Change in regulation of influenza virus vRNA synthesis during adaptation to various hosts]

To evaluate the effect of laboratory passaging of influenza virus A/USSR/90/77 (H1N1) on the pattern of vRNA synthesis regulation in course of the one step infection cycle, we have used the viral variants adapted to growth in the continuous cell line MDCK or to the reproduction in the mice lungs in vivo. Enhancement of regulation was registered in the adapted variants as compared to the original virus strain. The results are discussed in connection with possible significance of the vRNA synthesis regulation for the efficiency of viral reproduction under natural conditions or in laboratory passaging.