Comparison of biological properties of A(H1N1) influenza virus strains isolated in 1947 and during the epidemic of 1977.

A comparative analysis of biological properties of A(H1N1) influenza virus strains isolated in 1977 and the prototypic strain isolated in 1947 was performed. The strains showed marked differences in the vivo and in vitro replication as well as in the sensitivity to inhibitors of normal animal sera and to interferon. Also, their neuraminidases displayed different sensitivity to detergents.

Protective effect of different mouse interferons in mice infected with encephalomyocarditis (EMC).

Antiviral activity of various preparations of mouse interferons (Mu-IFN) administered prophylactically by the intranasal route 4 h before intranasal infection of mice with EMC virus was studied. In spite of the same activity of Mu-IFN preparations in vitro, their antiviral effect in vivo displayed differences. The "alveolar" Mu-IFN induced with NDV obtained in the upper respiratory tract, appeared to be the most effective interferon preparation in the prophylaxis of viral infection in mice.

The effect of experimental infection of mice with encephalomyocarditis (EMC) virus on interferon production by alveolar and peritoneal cells in vitro.

After infection of mice with EMC virus, dose-dependent increase or decrease of the synthesis of in vitro Newcastle disease virus (NDV)-induced interferon was observed in alveolar and peritoneal cells. It was shown that peritoneal cells from mice with mild course of the infection (infecting dose 0.2-1.

Interferon and humoral immune response in experimental influenza: infection with A/PR8 virus adapted to the mouse.

Inbred 129/Ao/Boy mice were infected with various doses of AO/PR8/HONI influenza virus. Replication of virus, synthesis of endogenous interferon and antibodies were measured. The infected mice were the source of alveolar and peritoneal cells which were used for the in vitro induction of interferon with Newcastle Disease virus (NDV).