[Antigenic and biological characteristics of influenza virus A strains isolated in 1985]. / Antigennye i biologicheskie osobennosti shtammov virusa grippa A, izolirovannykh v 1985 g.

The antigenic structure of hemagglutinin of influenza A virus (H3N2) strains isolated in 1985 was studied using a series of monoclonal antibody to A/Dunedin/4/73/A (H3N2) and A/Bangkok/1/79/A (H3N2), and biological and physico-chemical properties of these strains were compared with those of influenza A (H3N2) virus of 1983 and reference A (H3N2) of 1979-1984 (the rate of adsorption on chick erythrocytes and eluting activity, thermostability of hemagglutinin and neuraminidase, sensitivity to nonionic detergents, sensitivity to remantadine, analysis of virion polypeptide composition). A high degree of heterogeneity of the 1985 strain population of influenza A (H3N2) virus was revealed both in the antigenic structure of hemagglutinin and in all the biological and physico-chemical parameters tested. It was suggested that the A/Caen/1/84 strain originated not from A/Philippines/2/82 but directly from A/Texas/1/77.

[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.

[Isolation and study of the properties of IgG from antisera to influenza virus proteins]. / Poluchenie i issledovanie svoistv IgG iz antisyvorotok k belkam virusa grippa.

IgG to internal (NP, M) and external (HA, NA) proteins of influenza virus were isolated from immune rabbit sera using caprylic acid. The IgG retained their specificity and activity, worked in HI, lectin test, and enzyme-immunoassay. IgG migrated towards cathode in electrophoresis on acetate cellulose. Electrophoresis in polyacrylamide gel revealed a heavy chain (55,000) and a light chain (25,000) in IgG molecule. Different methods revealed changes in IgG structure after lyophilization. The possibility of recovering IgG from rat sera using caprylic acid was demonstrated. A comparative analysis of IgG recovered by means of caprylic acid as well as by polyethylene glycol or ammonium sulphate showed the IgG recovered with caprylic acid to contain less admixtures and to be suitable for use in immunological tests without additional purification.

[Biological consequences of breaks and reunions of disulfide bonds in influenza virus proteins]. / Biologicheskie posledstviia razryvov i vossoedinenii disul'fidnykh sviazei v belkakh virusa grippa.

Consequences of chemical breakage of native disulphide bonds in influenza virus neuraminidase and hemagglutinin glycoproteins induced by mercaptoethanol treatment were studied. Under conditions of blocked reoxidation of thiol groups, this treatment led to significant inhibition of hemagglutinating activity and infectivity of virus particles, and to a lesser inhibition of neuraminidase activity, as well as to promotion of endogenous proteolytic activity. Analysis of virus particles proteins by polyacrylamide gel electrophoresis indicated association of these biological effects with breakage of disulphide bridges, mainly in hemagglutinin glycoproteins. Under certain conditions, the proteins were capable of reformation of disulphide bridges as manifested in restoration of virion biological activity and electrophoretic characteristics of proteins.

[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.

[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.

[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.

[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.