[Gangliosides--specific receptors for the influenza virus].

The capacity of two gangliosides, GD1a and GT1b isolated from bovine brain to function as specific receptors of influenza virus was determined. A primary chick fibroblast culture was treated with neuraminidase to destroy natural receptors, the cells were loaded with gangliosides GD1a and GT1b, inoculated with 3H-uridine-labeled virus, and virus adsorption and penetration into the cell nucleus were determined. Both gangliosides were shown to restore virus adsorption to the cell surface and penetration of viral structures into the cell, GT1b facilitating more effective transportation of viral structures into the nuclei than GD1a and inducing penetration into the nuclei nearly 1.

Uncoating of a rimantadine-resistant variant of influenza virus in the presence of rimantadine.

A rimantadine-resistant variant of the Texas strain of influenza virus (Tr) was obtained by serial passages in eggs in MDCK cells in the presence of the drug, and its uncoating in MDCK cells was compared to that of the sensitive variant (Ts). First and second steps of uncoating were defined respectively by the appearance of subviral particles (SVP) in nuclear-associated cytoplasm (NAC) and ribonucleoproteins (RNPs) in nucleoplasm. In cells infected with Ts, SVP and RNPs were revealed in NAC, while in the presence of rimantadine RNPs were neither found in NAC nor in the nucleoplasm.

Influenza virus uncoating in infected cells and effect of rimantadine.

Uncoating of influenza virus (strain WSN) in MDCK cells was studied by following the fate of the virus labelled with radioactive precursors. The accumulation of subviral components of input virus was observed in nuclear-associated cytoplasm (NAC) obtained by treatment of the nuclei with citric acid. Two types of subviral components were found there, ribonucleoproteins (RNPs) and larger subviral particles (SVP) containing RNPs in association with M protein.

[Influenza virus penetration into the cells of a continuous dog-kidney line].

The penetration of the influenza virus (WSN) into MDCK cells and its intracellular fate was studied using electron microscopy of ultrathin sections of infected cells at early steps of infection, and biochemical analysis of intracellular subviral components. In electron micrographs, the virus particles absorbed on the cells and located inside phagosomes were detected. In both the cases, the fusion of the virus with cell envelopes was distinctly seen.

[Remantadine binding with influenza virus nucleoids in vitro and infected cells].

Interactions of the tritium-labeled antiviral preparation remantadine with nucleoids and ribonucleoprotein (RNP) of influenza virus were studied. The studies were carried out both in vivo, in infected cells, and in vitro upon direct contact of the preparation with subviral structures isolated from the infected cell and from virions. Autoradiography of the cells treated with 3H-remantadine showed its association with nuclei (possibly with nuclear membranes).