[Influenza inhibitor of the host serum RNAse]

From soluble proteins of influenza A viruses the author isolated, partially purified, and concentrated an inhibitor of host serum RNase, possessing no infectivity or neuraminidase activity, having the virus-specific antigen and, apparently, a lipoprotein composition, inhibiting RNAse activity by forming a complex with the enzyme and substrate, and considered to be one of the factors of virus pathogenicity acting on the molecular level. Antigenic relationships between RNase inhibitors of hierarchically remote influenza viruses were found. Immunization of mice with the inhibitor antigen prevents inhibition of serum RNAse activity after infection, and vaccination with the inhibitor antigen in combination with whole-virion killed vaccine significantly increased the protective effectiveness of the artificial immunity in experiments. The inhibitor preparation obtained is anaphylactogenic.