[Comparative study of the biophysical properties of the ribonucleoproteins of type A influenza viruses].

The sedimentation and density properties of ribonucleoproteins were studied with different strains of influenza type A virus: A/turkey/Wisconsin/66, A/swine/Iowa/15/31, A/horse/Prague/56, antigenic (A/H3Neq1) and biological (MRC-11) recombinants of the A/Port-Chalmers/1/73 strain. In all the viruses under study, ribonucleoprotein (RNP) was found to be heterogeneous and to sediment in a zone of 30-70 S. Variability in the distribution of fragments in different strains was revealed. In A/turkey/Wisconsin/66 and MPC-11 strains the highest radioactivity was found in the zone of "heavy" fragments (60-70 S), in A/horse/Prague/56 and A/swine/Iowa/15/31 strains it was prevalent in the zone of 40-50 S. In recombinant A(H3Neq1) the distribution of radioactivity varied in different tests. The buoyant density in cesium chloride in all RNP compenents was found to be similar, 1.34-1.36 g/ml.