Parent and recombinant influenza virus A strains differing in the degree of remantadine sensitivity

: The pattern of inheritance in recombination of various degrees of sensitivity of influenza viruses to remantadine was studied and the genes responsible for the manifestation of this character with regard to the degree of the strain sensitivity to the inhibitor were determined. The results suggest that resistance to 10 microgram/ml remantadine in most cases was determined by the inheritance of the gene coding for the membrane protein, whereas the sensitivity to 10 microgram/ml remantadine most frequently correlated with inheritance of hemagglutinin of the strain sensitive to this inhibitor. The resistance to high remantadine concentration was shown to have features of a polygenic marker as indicated by the occurrence of intermediate forms among the recombinants. Influenza A (H1N1) viruses and strains with the antigenic structure of A (H3N2) isolated in 1979-1981 were more resistant to remantadine, in some cases even to subtoxic concentrations of it. Influenza A (H2N2) and A (H3N2) as a rule were sensitive even to low concentrations of inhibitor.