[Immunological analysis of the chronological sequence of the shift in the antigenic determinants of influenza virus A (H1N1) hemagglutinins]. / Immunologicheskii analiz khronologicheskoi posledovatel'nosti smeny antigennykh determinant gemaggliutininov virusa grippa A (H1N1).

The study of the antigenic composition of influenza A (H1N1) viruses of two circulation periods, 1933-1957 and 1977-1981, by the method of selective adsorption of highly active antihemagglutinating sera revealed the ways of antigenic variability of drift variants. The antigenic composition of the hemagglutinin of H1N1 viruses of the second circulation period was found to be similar to that of H1N1 viruses isolated in 1950-1953.

[Antigenic markers in the hemagglutinins of influenza type A viruses (H1N1) from various periods of circulation]. / Antigennye markery v gemaggliutininakh virusov grippa tipa A (H1N1) razlichnykh periodov tsirkuliatsii.

Hyperimmune rabbit sera were examined by specific adsorption tests for influenza viruses H1N1 isolated in 1942-1952. A comparative immunological analysis revealed the presence of three antigenic determinants in hemagglutinins (HA) of A/Bel/42, A/Weiss/43, A/FM/1/47 and A/FLW/52 viruses. Adsorption of antisera with different drift-variants of H1N1 produced monoreceptor sera to individual antigenic determinants of HA by means of which marker antigens can be identified in HA of viruses isolated in different periods, and one may have an idea of evolutionary variability of influenza virus.

[Antigenic structure of the hemagglutinin of H1N1 influenza viruses studied by radioimmunological analysis]. / Izuchenie antigennoi struktury gemaggliutinina virusov grippa H1N1 metodom radioimmunologicheskogo analiza.

To elucidate the antigenic structure of influenza A (H1N1) viruses of different circulation periods (1947-1979) the criterion of participation of viruses of a constant test-group in competition for antibody from hyperimmune rabbit sera in radioimmunoassay (RIA) was used. The "set" of competing viruses varied with each immunospecific serum in relation to the immobilized strain for which the competitive capacity was studied. Each definite "set" of competing viruses was used as a marker of a certain type of antigenic determinant detected with a given test serum. Analysis of distribution of antigenic determinants and nonimmunogenic areas of hemagglutinin in the strains tested showed the drift nature of changes of the hemagglutinin antigenic properties. These changes may be grouped in 4 large antigenic regions, A, B, C, and D which appear to correspond to the "antigenic sites" revealed by Gerhard et al. by the monoclonal antibody procedure. Antigenic changes occur mainly in 3 of the above regions: A, B, and C in viruses of the first circulation period, and in B, C, and D in viruses of the second circulation period. Thus it has been shown that analysis of the antigenic structure of hemagglutinin by reciprocal radioimmunoassay of immunospecific sera to strains of the same subtype may be used as a tool for antigenic site mapping.

[Antigenic determinants of the hemagglutinins of influenza viruses of the "Spanish era"]. / Antigennye determinanty gemaggliutininov virusov grippa "ispanskoi éry".

Fractions of immunoglobulins G isolated from highly active hyperimmune rabbit sera and inhibitor-free antisera for influenza A viruses of the "Spanish" era different periods (1930-1978) were tested with a wide spectrum of human and animal viruses by the HI and CF tests. In hemagglutinins of Hswl, H0, and H1 viruses common antigens were found dissimilarly expressed in different variants as indicated by both various degrees of serological activity of the viruses and by great differences in the availability of cross-reactive antibody in various sera.

[Antigenic determinants of human influenza viruses among the influenza viruses isolated from animals]. / Antigennye determinanty virusov grippa cheloveka v sostave grippoznykh virusov, vydelennykh ot zhivotnykh.

Comparative studies of the antigenic properties of hemagglutinin (HA) of animal and human viruses revealed both similarities between them and complete differences in the composition of antigenic determinants. Avian influenza viruses A/chicken/Kamchatka/12/71, A/pintail/Primorie/730/76, and A/bat/Alma-Ata/73/77 were completely identical with human strains of influenza virus. Influenza A/horse/Miami/63 contains one antigenic determinant H3.1.HA of A/tern/Turkmenia/18/73 (Hav7) viruses has a peculiar set of antigens. Apart from two antigenic determinants H3.1 and H3.3 inherent in human virus strains, HA of A/tern/Turkmenia/18/73 virus contains an antigenic determinant the population of antibodies to which shows no relation to HA of subtypes Hav2-Hav9.

[Hemagglutinin antigenic determinants of influenza viruses H1N1 isolated 1953-1957 in the composition of the hemagglutinins of influenza viruses H1N1 isolated 1978-1979]. / Antigennye determinanty gemaggliutininov virusov grippa H1N1 1953-1957 gg. vydeleniia v sostave gemaggluitininov virusov grippa H1N1 1978-1979 gg. vydeleniia.

Immunological analysis of antigenic determinants in the composition of hemagglutinins (HA) of H1N1 viruses isolated in the epidemic season of 1978-1979 showed their difference from A/USSR/090/77 virus HA. The A/Brazil/11/78 HA is characterized by 3 antigenic determinants two of which are identical with those of A/USSR/090/77 HA and one shows relationship with HA determinant of A/Omachi/1/53 virus, A/Fukushima/103/78 and A/Kagoshima/22/79 HAs are characterized by 1 determinant common with that of A/USSR/090/77 HA and 2 determinants identical with A/Omachi/1/53 virus HA. HAs of these viruses contain a determinant responsible for the antigenic relation of A/Omahi/1/53 HA with that of H1N1 viruses isolated in 1956-1957. The results suggest that the antigenic drift of HA of H1N1 viruses isolated in 1977-1979 occurs by the cycle characteristic of HA of H1N1 viruses isolated in 1950-1957. By the sensitivity to alpha-, beta-, and gamma-inhibitory of rabbit serum H1N1 viruses isolated in 1947-1957 and in 1977-1979 are quite similar with the exception of A/USSR/184/79 virus showing high sensitivity to gamma-inhibitors like H2N2 and H2N2 viruses.

[New antigenic determinant in the makeup of influenza type A(H3N2) virus hemagglutinins]. / Novaia antigennaia determinanta v sostave gemaggliutininov virusov grippa tipa A(H3N2).

Influenza A (H3N2) viruses isolated during 1979 influenza epidemic are characterized by the presence in their hemagglutinins of both antigens similar to those found in previous isolates of the same type and a qualitatively new antigenic determinant also found in the hemagglutinin of H/South Australia/1/77 virus.

[General antigenic determinants in the hemagglutinin composition of influenza viruses H0, H1 and Hsw1]. / Obshchie antigennye determinanty v sostave gemaggliutininov virusov grippa H0, H1 i Hsw1.

The antigenic properties of influenza type A viruses with hemagglutinin subtypes H0, H1, and Hsw1 were studied by hemagglutination-inhibition test, indirect solid-phase radioimmunoassay and biological neutralization test using highly potent hyperimmune rabbit sera. The results obtained indicate the presence of common antigenic determinants in hemagglutinins of H0, H1 and Hsw1 viruses.