Indication and study of antigenic properties of influenza virus internal proteins by means of monoclonal antibodies.

Influenza A and B viruses isolated from animals and man were studied by solid phase radioimmunoassay (SP RIA) using monoclonal antibodies to the A/Dunedin/4/73 strain nucleoprotein (NP). Only influenza A viruses isolated before 1980 interacted with the monoclonal antibody set used, while strains isolated between 1980 and 1983 failed to do so. It was shown that RIA employing monoclonal antibodies was useful for rapid identification of influenza virus NP in the allantoic fluid containing fresh influenza A virus isolates.

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.

Antigenic structure and biological characteristics of influenza strains isolated in the USSR during the 1974/75 epidemic.

Antigenic analysis of strains isolated in the USSR during the epidemic in 1974/1975 showed differences in the hemagglutination inhibition test and in neuramidase activity with antisera against three reference strains. Strains isolated in a later period of the epidemic were classified into subgroup A/Port Chalmers/1/73. Nearly all strains were effective inducers of interferon and were susceptible to this inhibitor of virus replication.

Strain differences in electrophoretic mobility of influenzavirus A polypeptides.

Slab polyacrylamide gel electrophoresis of Influenza-virus A strains varying in antigenic composition of the envelope and in the natural host species showed the nucleprotein and membrane proteins to have a standard molecular weight of 58,000 and 24,000 daltons, respectively. The electrophoretic mobility and molecular weights of the light and heavy chains of haemagglutinin varied in the strains under study. The differences observed persisted on passaging and were transferred upon genome recombination.

Return of epidemic A1 (H1N1) influenza virus.

Limited outbreaks of influenza were reported in the far east of the U.S.S.