[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.

[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.

[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.

[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.

[Comparative evaluation of the sensitivity of immunofluorescence methods, immunoenzyme analysis and the lectin test for the rapid diagnosis of influenza]. / Sravnitel'naia otsenka chuvstvitel'nosti metodov immunofliuorestsentsii, immunofermentnogo analiza i lektin-testa dlia ékspress-diagnostiki grippa.

Comparative study of the sensitivities of immunofluorescent microscopy (IFM), enzyme immunoassay, (EIA), and lectin test (LT) in the detection of influenza virus antigen in nasopharyngeal washings from patients with influenza, acute respiratory diseases, pneumonia, and laryngitis has been carried out. EIA modification (used in this study) based on the detection of a complex of viral core proteins (M + RNP) has been shown to be no less sensitive than IFM and suitable for use in the rapid diagnosis of influenza. It can be used in combination with other methods. The optimum time for collecting the washings off is day 2 from the disease onset for analysis by EIA technique and day 4 for LT.

[Immunostructure of the population to the influenza C virus]. / Izuchenie immunostruktury naseleniia k virusu grippa C.

Examinations of 842 blood serum specimens from children varying in age from 0 to 14 years and 975 blood serum specimens from adults of 20-60 were carried out. The infants of 0-6 months of age may be considered to be immunologically protected by passively transmitted maternal antibodies. The formation of active immune response occurs at the age of 6 months to 14 years with subsequent antibody persistence and additional latent immunization in older age. Children of 6 months to 7 years are most susceptible to infection with influenza C virus. Among the adult USSR population, antibody to influenza virus was found in approximately 85.7% of subjects. The proportion of seropositive subjects varied in different parts of the country. The greatest numbers of positive findings and high levels of antibody to influenza C virus were found in the adult and child population of Moscow.

[Mobility study of influenza C virus proteins in cellulose acetate electrophoresis]. / Izuchenie podvizhnosti belkov virusa grippa C v élektroforeze na atsetate tselliulozy.

Four strains of influenza C virus were studied by cellulose acetate electrophoresis. All of them were found to contain super-capsid proteins destroyed by electrophoresis apparently due to contact with sodium dodecylsulphate. According to Laver's classification, influenza C viruses may be placed with Group 3 viruses. Among major virion proteins of influenza C viruses matrix protein was found to be the most stable forming a separate protein band on cellulose acetate, and it may be readily identified and eluted from paper in preparative amounts.

[Demonstration and study of the internal proteins of the influenza B virus using solid-phase radioimmunological analysis]. / Indikatsiia i izuchenie vnutrennikh belkov virusa grippa B s pomoshch'iu tverdofaznogo radioimmunologicheskogo analiza.

Internal proteins of influenza B/USSR/14/80 virus retaining their antigenic and immunogenic activities were obtained by electrophoresis in 1% agarose. Antisera to eluted NP and M polypeptides were prepared. Study of influenza B viruses isolated in 1940-1984, performed by solid-phase radioimmunoassay, revealed no differences in the antigenic properties of nucleoprotein and matrix protein, except in the B/Yamagata/73 virus.

[Use of immunoenzyme analysis for the detection and differentiation of influenza viruses A, B and C]. / Ispol'zovanie immunofermentnogo analiza dlia indikatsii i differentsiatsii virusov grippa A, B i C.

Test systems for ELISA, containing antibodies to internal or supercapsid proteins and intended for the detection and differentiation of influenza A, B and C viruses in small amounts, have been developed. The possibility of using these systems for the determination of viruses both in material obtained directly from humans and in chick embryo isolates has been demonstrated.

[Radioimmunological study of the antigenic conformity of the hemagglutinins of vaccinal and epidemic strains of influenza virus]. / Izuchenie radioimmunologicheskim metodom antigennogo sootvetstviia gemaggliutininov vaktsinnykh i épidemicheskikh shtammov virusa grippa.

Antigenic relationships of the vaccine A/Victoria/35/72 strain and vaccine candidate A/Khabarovsk/15/76 and recombinant RK-5 strains with hemagglutinins of the epidemic A/Victoria/3/75, A/Leningrad/173/75, and A/Victoria/112/76 strains were studied by radioimmunoassay (RIA) in two test systems. Alongside with other tests RIA is useful and expedient for rapid and accurate quantitative evaluation of the antigenic conformity of influenza virus strains under comparison.

[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.

[Sedimentation characteristics of the virions and subviral particles of influenza C viruses]. / Sedimentatsionnye kharakteristiki virionov i subvirusnykh chastits virusov grippa C.

Investigation of sedimentation and some other properties of subviral particles and native virions of influenza C viruses was carried out in comparison with influenza A virions. Sedimentation rate of influenza C viruses was found to be 0.6 of that of influenza A viruses, the optical density peak coincided with the peaks of hemagglutinating and infectious activities of both influenza A and influenza C viruses. Studies with 4 influenza C virus strains isolated in different years revealed no differences in their sedimentation rates and the curve pattern. Electron microscopic, electrophoretic, and sedimentation analyses showed higher fragility of influenza C virions than those of influenza A virus, and their trend to self-disintegration. Our data showed significant differences in the effect of proteases on influenza A and C viruses. With due regard to these differences, we modified the method satisfactorily used for production of influenza A subviral particles. Some properties of subviral particles of influenza C virus were studied.

[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.

[Test system for detecting and differentiating the influenza virus by an immunoenzyme method]. / Test-sistema dlia indikatsii i differentsiatsii virusa grippa immunofermentnym metodom.

Detection and differentiation of small amounts of influenza A and B viruses was done by enzyme-immunoassay based on detection of the complex of internal proteins. It was shown that two kinds of sera to the complex of internal proteins could be used: sera against disrupted viruses grown in a different system (mice or cell culture) and containing almost no CAM component for virus detection in the allantoic fluid of chick embryos, and sera to preparations of viruses grown in chick embryos and disrupted with detergents for elimination of virion surface determinants (wastes of subunit vaccine) for virus detection in nasal secretions of vaccinated subjects. The test-systems containing antibodies to the complex of internal proteins were shown to be as sensitive and specific as those containing antibodies to pure M protein and RNP.

[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.

[Changes in the antigenic composition of virus A (H1N1) hemagglutinin in 1977-1982 detected by using monoclonal antibodies]. / Izmeneniia antigennoi kompozitsii gemaggliutinina virusov A (H1N1) v 1977-1982 gg., vyiavlennye s pomoshch'iu monoklonal'nykh antitel.

Parallel studies of influenza A (H1N1) strains by the micro-HI method using monoclonal antibodies, antivirion sera obtained by immunization of rats, and by the immunoadsorption of rats, and by the immunoadsorption test showed monoclonal antibodies to detect the antigenic drift most definitely. Among 156 strains isolated in 1977-1982 in various parts of the USSR and abroad, 6 antigenic drift variants were detected differing in the content and combination of epitopes recognized by different monoclonal antibodies to the A/USSR/90/77 strain. Three of them have first been found. The quantitative decrease in an epitope activity was established to precede its disappearance and may be used as a prognostic sign. Among 5 epitopes tested, most labile were those recognized by monoclones Nos. 264, 110, and 18. They began to disappear since 1978-1979. The epitopes recognized by monoclones Nos. 70 and 22 were most conservative and were still found in the strains isolated in 1982.

[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.