[Influenza vaccine stimulation of antibodies to different variants of influenza A virus].

The capacity of live influenza type A (H3N2) vaccines to produce antihemagglutinins and antineuraminidase antibody to drift variants of a given serosubtype emerging later than the vaccine strain was studied. For this purpose, a wider set of antigens was used to examine retrospectively by the HI and virus elution from erythrocyte inhibition tests the paired sera from the subjects immunized in 1975 and 1976 with live vaccine virus strains similar to A/Port Chalmers/1/73 (H3N2) and A/Victoria/3/75. These vaccines were shown to actively stimulate antibody production in titres of 1:40 or higher to strains forestolling the vaccine strain by 1 (antihemagglutinins) and 2 (antineuraminidase antibody) degrees of the antigenic hierarchy. The intensity of production of both kinds of antibody to similar future strains depended on the intensity of immune response to the vaccine virus. By increasing the dose and frequency of administration of the virus serosubtype A (H3N2) to animals it was possible to intensify the production of antihemagglutinins and antineuraminidase antibodies to later drift variants of this agent with respect to the virus-immunogen. Volunteers immunized in 1983 with a commercial inactivated chromatographic bivaccine prepared from the strains similar to A/Bangkok/1/79 (H3N2) and A/Brazil/14/78 (H1N1) were found to intensively produce antihemagglutinins in titres of 1:40 or higher to viruses A/Philippines/2/84 (H3N2), A/Leningrad/167/83 (H3N2), A/Leningrad/3/82 (H1N1) but not to A/Dunedin/27/83 (H1N1) virus.