[Immunogenicity of attenuated reassortants of influenza A virus /Leningrad/134/47/57 (H2N2) for mice, depending on their genome]. / Immunogennost' dlia myshei attenuirovannykh reassortantov virusa grippa A /Leningrad/134/47/57 (H2N2) v zavisimosti ot sostava ikh genoma.

Reassortants of cold-adapted strain A/Leningrad/134/47/57 (H2N2) and virulent strain A/PR/8/34 (H1N1), modeling genomic composition of vaccinal strains, were tried in mouse experiments. Reassortants' genomes included the major part (5, 6, or 7) from cold-adapted strain and 1 to 3 genes of virulent strain. All the tested reassortants did not differ by temperature sensitivity or cold adaptation phenotypes, did not cause the death of mice, but differed by the level of reproduction in murine lungs and by immunogenicity. Strains with genomic formulas 6/2 (HA and NA of a virulent strain) and 5/3 (M) (HA, NA, and M of a virulent strain) were characterized by the highest immunogenicity. Reassortants including, besides HA and NA, PA gene 5/3 (PA) or inheriting only HA gene from strain A/pr/8/34 (H1N1) were hyperattenuated and low immunogenic.