[Antigenic specificity of the neuraminidases of epidemic strains of influenza A/H3N2 viruses circulating in the USSR 1983-1985]. / Antigennaia spetsifichnost' neiraminidaz épidemicheskikh shtammov virusov grippa A/H3N2, tsirkulirovavshikh v SSSR v 1983-1985 gg.

The antigenic properties of neuraminidase of the epidemic strains of 1983-1985 were studied by means of lectin test and thiobarbituric method using polyclonal sera and monoclonal antibody. Populations of the viruses with respect to antigenic relationships of neuraminidase were shown to be heterogeneous. A considerable portion of the strains occurring in 1985 underwent antigenic drift from the reference A/Philippines/2/82 strain. The epidemic novelty of some strains was due to changes in only one supercapsid protein-neuraminidase.

[Operative assessment of the influenza situation based on a complex accounting of standardized indices of incidence and data on rapid diagnosis]. / Operativnaia otsenka situatsii po grippu na osnove kompleksnogo ucheta standartizovannykh pokazatelei zabolevaemosti i dannykh ékspress-diagnostiki.

The paper described a method allowing most objective and operative evaluation of the influenza situation in the autumn-winter period, the detection of the onset of influenza epidemic in a given population area, and characterization of the intensity of the epidemic. The development of a more accurate method of operative evaluation of the influenza situation is necessary because influenza is one of widely prevalent virus diseases which still plays a significant role in human pathology and simultaneously takes away from productive labor tremendous numbers of workers. Follow-up of the incidence levels is based on the idea of comparison of the actual data with standardized parameters. These parameters (incidence at the start week, the pace of epidemic increase, the critical seasonal coefficient) are calculated by weekly data of the basic period for a number of years for each town under study on the basis of comparison with the mean minimal level of influenza and ARD incidence (summer normal level) and also the use of mathematical statistics apparatus. To establish epidemiologically unfavourable situation it is necessary that operatively estimated current parameters (analogous with pre-calculated standardized ones) be equal to or exceeding the standardized parameters. The methods of rapid diagnosis are used additionally for identification of the etiology of the starting outbreak or epidemic. The use of the developed methods is exemplified in the paper by practical estimates of the influenza situation in Moscow in the seasons of 1983-1984 and 1984-1985.

[Incidence of influenza in a large city 1978-1981]. / Rasprostranenie grippa v usloviiakh krupnogo goroda v 1978-1981 gg.

Comparison of dissemination of influenza during three seasons, 1978-1981, in Moscow was done with parallel registration of the total incidence of influenza and ARD as well as the frequency of influenza A and B cases confirmed by immunofluorescent express diagnosis method. The weekly registration of the express diagnosis results was found to reflect quite accurately the periods of increased spread of influenza and to be a significant addition to the currently used analysis of the summary incidence increasing the accuracy of operative evaluation of the epidemic situation under conditions of large cities.

[Characteristics of the distribution of influenza A and B in various geographical regions of the USSR]. / Osobennosti rasprostraneniia grippa A i B v raznykh geograficheskikh raionakh SSSR.

The results of a comparative analysis of laboratory-confirmed cases of influenza A and B recorded annually in October-May from 1977 to 1981 in four towns located in different geographical regions of the country are reported. During this period, influenza A represented by varieties A (H1N1) and A (H3N2) and B were found to have been recorded in all the towns under study. The periods of the maximum number of the laboratory-confirmed cases recorded coincided generally with the periods of increased clinical incidence of ARD. There were instances, however, when during the periods of elevated ARD morbidity the number of laboratory-confirmed cases of influenza increased insignificantly. Peculiar features were found in fluctuations of the incidence of laboratory-confirmed influenza cases in different geographical regions of the country.

[Comparative analysis of the dynamics of antibodies to influenza A (H1N1) and A/Hong Kong/1/68 (H3N2) in the sera of a healthy population]. / Sravnitel'nyi analiz dinamiki antitel k shtammam virusov grippa A (H1N1) i A/Gonkong/1/68 (H3N2) v syvorotkakh krovi zdorovogo naseleniia.

A comparative analysis of the dynamics of antibodies against A(H1N1) and A/Hong Kong/I/68 (H3N2) influenza viruses was carried out in the blood sera of healthy population in some cities of the USSR. The data obtained suggest that anamnestic antibody production can be stimulated only by the drift- and not by the shift-variants of viruses, i.e. by those with varying hemagglutinin serotypes.

[Effective methods of obtaining antisera to hemagglutinin H3]. / Effektivnye metody polucheniia antisyvorotok k gemaggliutininu H3.

Schedules for production of antisera to pure influenza A virus hemagglutinin (H3) in rats and rabbits are described. The antisera prepared in rats were shown to be better than rabbit sera as they had low levels of inhibitors readily eliminated by heating. The best sera were obtained by immunizations of rats into the tail. Both rat and rabbit antisera, in addition to the HI test, can be used satisfactorily in the immunodiffusion test and in radioimmunoassay.

[Age profile of the antihemagglutinins and antineuraminidase antibodies in type A influenza (author's transl)]. / Vozrastnoi profil' antigemaggliutininov i antineiraminidaznykh antitel pri grippe tipa A

Antineuraminidase and antihemagglutinating antibody studies were carried out in parallel in sera from subjects born in Bulgaria in 1968-1972, 1956-1960, 1946-1950, 1925-1935 and 1917-1920. It was found that the amount of both antineuraminidase and antihemagglutinating antibody in sera from normal subjects could vary depending upon the year of birth and the strain used for the test. The antibody spectrum was most narrow in children under 4 and wider in subjects born before 1925. Serograms of the age distribution of antineuraminidase antibody were different in 4 out of 5 strains used which confirmed the hypothesis of Francis and Davenport of the more solid immunological response to the first exposure to virus. Parallel examinations of the antibody spectrum in human sera confirmed differences in the antigenic specificity of the "active center" of neuraminidases of A/Hong Kong/1/68 (H3N2) and A/Singapore/1/57 (H2N2) viruses and for the first time provided evidence attesting to the existence of similar strain differences in neuraminidases belonging to the N1 group. Examinations for antineuraminidase antibody in addition to antihemagglutinins increase the effectiveness of evaluation of the immunological structure of the population.

[Detection of influenza virus C antibodies in the gamma globulins and native sera of children]. / Obnaruzhenie antitel k virusu grippa C v gamma-globulinakh i nativnykh syvorotkakh detei.

Influenza C virus has been found to be sufficiently widely prevalent in the human population of the USSR. Our evidence indicates its circulation in different climatic zones of the USSR. It has first been shown that the concept of "original antigenic sin" formulated by T. Francis for influenza A and B viruses is applicable for the evaluation of the immune response to infection with different influenza C virus strains. Our evidence allows an age-group of children most susceptible to influenza C virus infection to be distinguished and a preparation for prevention and treatment of this infection proposed.

[Biological properties of strains of influenza virus that caused the epidemic of 1974-1975]. / Biologicheskie osobennosti shtammov virusa grippa, obuslovivshikh épidemiiu 1974-1975.

The biological features of the strains of influenza virus isolated in the 1974-1975 epidemic were compared with those of the strains which had circulated earlier. Most of the properties examined (toxicity for mice, sensitivity to gamma-inhibitors, thermostability of hemagglutinin and neuraminidase) in strains isolated in 1974-1975 did not differ from those in strains of previous epidemics. Clear-cut differences between the new and earlier strains were found in the studies of their chromatographic profiles.

[Electrophoretic characteristics of the proteins and the preparative production of neuraminidase from the A/turkey/Wisconsin/66 (Hav6N2) strain of the avian influenza virus]. / Elektroforeticheskaia kharakteristika belkov i preparativnoe poluchenie neiraminidazy shtamma A/indiuk/Viskonsin/66 (Hav6N2) virusa grippa ptits.

A combination of electrophoresis in a single plate of polyacrylamide gel with preparative production of subunits upon electrophoresis in acetate cellulose was used for the analysis of the polypeptide composition of the A/turkey/Wisconsin/66 strain. Seven classes of proteins with certain functional significance and 4 minor components were detected. A preparation of neuraminidase could be obtained which has enzymatic and antigenic activity, and a molecular mass of 68,000 daltons. Some features of the polypeptide composition were revealed, including the presence of uncleaved hemagglutinin under reducing conditions and a decreased content of the light chain of hemagglutinin.

[Comparative characteristics of the biophysical properties of influenza A, B and C proteins]. / Sravnitel'naia kharakteristika biofizicheskikh svoistv belkov virusov grippa A, B i C.

A comparative analysis of electrophoregrams of influenza A, B, and C virus proteins in polyacrylamide gel and in agarose was made. Separation of proteins was similar in three influenza C virus strains tested and differed from that of influenza A and B virus proteins. The possibility of preparative isolation of supercapsid and internal proteins of influenza C virus with preservation of their antigenic and immunogenic properties was demonstrated. Antisera to internal proteins and hemagglutinin of influenza C virus were prepared. Both antisera reacted in the double immunodiffusion test and ELISA, and antiserum to hemagglutinin also in hemagglutination inhibition test.

[Isolation of natural cold variants from influenza virus strains similar to A/Bangkok/1/79 (H3N2)]. / Vydelenie estestvennykh kholodovykh variantov iz shatmmov virusov grippa, skhodnykh s A/Bangkok/1/79 (H3N2).

Two natural cold variants were isolated from influenza virus strains similar to A/Bangkok/1/79 (H3N2) and their antigenic and some biological properties were studied in comparison with the original strains. No correlation between the temperature sensitivity of the strains and other properties was found.

[Physiochemical properties of purified and virion neuraminidases of the influenza B viruses]. / Fiziko-khimicheskie svoistva ochishchennykh i virionnykh neiraminidaz virusov grippa B.

A method for isolation of neuraminidase using pronase has been developed. Purified preparations have been recovered from two influenza B virus strains, B/Mass/3/66 and B/USSR/14/80. Physico-chemical properties of neuraminidases were compared; optimal conditions for the determination of neuraminidase activity of these strains were determined. Strains differences in thermostability, optimal pH, specificity to substrates were established. Neuraminidases, isolated or present in virions, were shown to be identical in enzymatic characteristics but to differ in thermostability.

[Analysis of the antigenic specificity of the neuraminidases of influenza B viruses isolated in different years]. / Analiz antigennoi spetsifichnosti neiraminidaz virusov grippa B, izolirovannykh v raznye gody.

The antigenic structure of neuraminidases of influenza B viruses isolated in 1940-1984 was studied. Lectin test has first been employed for analysis of influenza B virus neuraminidase. The antigenic composition of neuraminidases of these viruses was shown to be different. The strains isolated in the epidemic of 1983-1984 underwent further drift of the neuraminidase component and represent a heterogeneous group in this respect. The use of monospecific antiserum to purified neuraminidase helped specify antigenic relationships of this protein.

[Use of agarose for isolating influenza virus proteins retaining a high immunogenicity]. / Ispol'zovanie agarozy dlia izoliatsii belkov virusa grippa, sokhranivshikh vysokuiu immunogennost'.

A method of influenza virus separation in agarose was modified. The possibility of using agarose of the national make and Difco agar was established. RNP and M proteins were isolated. Highly active anti-M and anti-RNP sera were prepared which work well in the ELISA and RIA.

[Determination of the neuraminidase specificity of influenza A and B viruses using a modified lectin test]. / Opredelenie spetsifichnosti neiraminidazy virusov grippa A i B s pomoshch'iu modifitsirovannogo lektin-test.

A highly purified lectin was obtained from peanuts. The lectin test was modified for determination of the neuraminidase activity of influenza viruses. The test was found to be useful for the determination of the antigenic specificity of neuraminidase. It was found to be 10-50 times as sensitive as the Aminoff test and more economic. The potentials of lectin test are discussed.

[Heterogeneity of monospecific antibodies to the hemagglutinin of influenza virus H3N2 studied by radioimmunological analysis]. / Izuchenie geterogennosti monospetsificheskikh antitel k gemaggliutininu virusa grippa H3N2 metodom radioimmunologicheskogo analiza.

Heterogeneity of antibodies against influenza virus hemagglutinin has been confirmed. Various subpopulations of antibodies to the A/Khabarovsk/15/76 hemagglutinin were demonstrated some of which showed greater affinity to MRC-11 hemagglutinin than to the HA of the strain inducing this antibody synthesis. Apparently subpopulations of antibodies with low affinity to their "own" epitopes in the hemagglutinin-immunogen may develop which, however, may show a sufficiently high affinity to these epitopes in hemagglutinins of other strains.

[Group and strain-specific determinants of the influenza virus nucleoprotein]. / Gruppovye i shatmmospetsificheskie determinanty nukleoproteida virusa grippa.

An antiserum to a purified nucleoprotein preparation of influenza virus recombinant A/MRC/11 obtained from A/Port Chalmers/1/73 and A/PR/8/34 strains, was examined for the presence of antibody before and after its adsorption with sodium sarcolysil sulphate-disrupted influenza. A viruses by the methods of radial and double immunodiffusion. The antiserum was found to contain both group- and strain-specific (for MRC-11 nucleoprotein) antibodies. In radial immunodiffusion tests MRC-11 nucleoprotein showed the greatest affinity to A/PR/8/34 nucleoprotein and differed from A/Scotland/860/74 and A/USSR/090/77.

[Antigenic and biological characteristics of the A (H1N1) strains that caused the 1977--1978 epidemic]. / Antigennye i biologicheskie osobennosti shtammov A (H1N1), vyzvavshikh épidemiiu 1977--1978 gg.

By the antigenic specificity of the surface subunits, hemagglutinin and neuraminidase, the influenza virus strains A (H1N1) isolated in 1977--1978 were related but not identical to the A (H1N1) strains circulating in 1950--1952. The A/FM/1/47 strain differed from the A/England/51, A/Pan/52 strains and A/USSR/090/77 strain by its antigenic relations with the A/Netherland/56 and A/Denver/57 strains. Biologically, the new A/H1N1/77 strains were similar to the reference strains circulating in 1947--1952 by any one feature.

[Antigenic similarity of the hemagglutinins of human and animal influenza A viruses studied by immunoadsorption]. / Issledovanie antigennoi obshchnosti gemaggliutininov virusov grippa A cheloveka i zhivotnykh metodom immunoadsorbtsii.

Antigenic relationships between human influenza A viruses containing hemagglutinins of HO and H1 subtypes and animal and avian influenza viruses Hsw1 and Hav5 were studied by immunoadsorption using inorganic base of the sorbent. Direct and indirect relations due to the presence in hemagglutinin of common antigenic determinants and hapten groups were revealed. The strains representing drift variations within one subtype differed by the spectrum of hapten determinants typical of other subtypes. No common determinant typical for all members of this group was isolated.