[Factors that cause a change in the antigenic structure of of the influenza virus hemagglutinin].

Crossing of norakin-resistant mutant NR1 of A/Waybridge (H7N7) strain of fowl plague virus (FPV) with human influenza virus strains produced recombinants inheriting the hemagglutinin (HA) gene of the NR1 mutant and neuraminidase (NA) genes of human influenza virus strains. The R120 recombinant produced by crossing of NR1 with A/Taiwan/1/86 (H1N1) strain, unlike other recombinants and NR1 mutant, lost the capacity of reacting in H1 test with two monoclonal antibodies (MCA) to HA7: 71/4 and 46/6. The ts mutant A/FPV/Rostok which has ts-mutation in HA-gene also had changes in the antigenic specificity of HA. The RA and RB recombinants produced by crossing R120 with the A/Krasnodar/101/59 strain and inheriting HA-gene from R120 and NA-gene from A/Krasnodar/101/59 strain recovered the initial HA antigenic structure. No changes in the antigenic properties of HA were observed in the recombinants produced by crossing the original A/FPV/Waybridge strain with A/Taiwan/1/86 strain and inheriting HA-gene from the original A/FPV/Waybridge strain and NA-gene from A/Taiwan/1/86 strain. It is concluded that ts mutations in influenza virus HA-gene may be accompanied by changes in the antigenic specificity of this virus HA. The possibilities of manifestation of phenotypic suppression at the level of influenza virus virion membrane proteins and the causes of changes in the HA antigenic structure in this virus recombinants are discussed.