Ultrastructure and some biological properties of influenza A virus. II. Effect of physico-chemical factors on influenza A virus and its interferonogenic properties.

Influenza virus A/USSR/053/74/H3N2 was subjected to the effect of some physico-chemical factors: freezing-thawing, ultrasounds, long-term storage at 4 degrees C, hydrogen ions, formaldehyde. All the preparations were tested for virus infectivity, hemagglutinin titer, neuraminidase activity and ability of altered viruses for interferon induction in vivo. The preparations whose viral particles preserved the activity of surface antigens and neuraminidase activity in particular, were able to induce interferon in mice.