Analysis of Genome Composition and Reactogenicity of Recombinants of Cold-adapted and Virulent Virus Strains

Abstract

Temperature-sensitive (ts) mutations occurring in genes 1, 2 and 7 and 1, 5 and 7 were found in the cold-adapted (ts) attenuated influenza virus strains A/Leningrad/9/37/46 (H0N1) and A/Leningrad/134/17/57 (H2N2), respectively. The recombinants, obtained by crossing these cold-adapted strains with virulent influenza virus strains, had different genome structures and inherited 1-6 genes from the cold-adapted parents. Tests of reactogenicity of recombinants in volunteers showed all the recombinants to be non-reactogenic, irrespective of the number of genes inherited from the cold-adapted parent.