[Molecular composition of phenotypically mixed virions formed during mixed infection with influenza viruses A and B]. / Molekuliarnyi sostav fenotipicheski smeshannykh virionov, formiruiushchikhsia pri dvoinoi infektsii, vyzvannoi virusami grippa A i B.

Upon mixed infection of cultured cells by influenza viruses A/WSN/33 and B/Lee/40 the produced virions contain in their envelopes either hemagglutinin B/Lee/40, or hemagglutinins of both viruses, depending on their concentration ratio during infection. In the first case the population contains RNA segments and nucleoproteins (NP) of both viruses, in the second-exclusively RNA and NP of virus A/WSN/33. Results of immunoprecipitation with monoclonal antibodies to protein of virus A/WSN/33 with further analysis of immunoprecipitates by electrophoresis in polyacrylamide gels did not reveal the presence of virus ribonucleoproteins, containing NP of both viruses. The data obtained demonstrate the high of specificity of protein-protein recognition during reassembly of virion inner structures.

[Characteristics of virion formation during mixed infection with influenza viruses A and B]. / Osobennosti formirovaniia virionov pri smeshannoi infektsii, vyzvannoi virusami grippa A i B.

Simultaneous infection of MDCK cells with influenza A and B viruses at an equal multiplicity of infection leads to the synthesis of the proteins of both viruses. In the population of virions the hemagglutinin of influenza B virus prevails, whereas NP proteins of both viruses are present in similar quantities. Trypsin treatment of the double-infected cells resulting in the cleavage of the hemagglutinin molecules at the cell surface allows revealing the predominance of influenza B hemagglutinin on cell surface, although both hemagglutinins are accumulated in the cells. An impairment of the hemagglutinin transport to the cell surface as a possible additional mechanism of heterotypic interference and its possible effect on the polypeptide content of the phenotypically mixed virions are discussed.

[The use of immunosorption for the analysis of influenza virus RNA in intracellular viral ribonucleoproteins]. / Ispol'zovanie immunosorbtsii dlia analiza RNK virusa grippa, soderzhashcheisia vo vnutrikletochnykh virusnykh ribonukleoproteidakh.

Protein A-containing formaldehyde-fixed S. aureus (strain Cowan) was incubated with an antiviral serum or with a monospecific serum against NP protein, washed, and used as immunosorbent in order to isolate viral ribonucleoproteins (nucleocapsids) containing intact viral RNA from the extracts of influenza virus infected [3H]-uridine-labelled cells.

[Formation of mixed hemagglutinin trimers during double infection with influenza virus strains of the same subtype]. / Formirovanie smeshannykh trimerov gemaggliutinina pri dvoinoi infektsii, vyzvannoi shtammami virusa grippa, prinadlezhashchikh k odnomu podtipu.

Formation of hemagglutinin spikes in the course of the mixed infection of cell culture by two influenza virus strains belonging to the same antigenic subtype or to different subtypes was studied by means of immunoprecipitation of [14C]-labelled hemagglutinins from cell lysates. The immunoprecipitates were further analysed by polyacrylamide gel electrophoresis. Lysates of separately infected cells mixed before lysis were used as control samples. The analysis of immunoprecipitates revealed the formation of chimeric hemagglutinin spikes in the cells infected by the strains possessing hemagglutinins of the same subtype but not in the cells infected by the strains of different subtypes (H1 and H3). The results are discussed in connection with the homology of amino-acid sequences of influenza virus hemagglutinins.

[Immunoprecipitation, with an antiserum to ovalbumin, of protein NP from influenza A virus and of glycoprotein C from the herpes simplex type I virus]. / Immunopretsipitatsiia antisyvorotkoi k oval'buminu belka NP virusa grippa A i glikoproteina S virusa prostogo gerpesa tipa I.

Antisera to ovalbumin and to thyroliberin react in radioimmunoprecipitation and radioimmunoassay with NP protein of influenza A virus and C glycoprotein of herpes simplex virus whose mutual amino acid homology does not practically exceed the limits of homology in tripeptides. Both proteins contain a tripeptide area corresponding to thyroliberin tripeptide.

[Isolation of nuclei from influenza virus infected chick fibroblast cells]. / Vydelenie iader iz kletok kurinykh fibroblastov, zarazennykh virusom grippa.

Three methods of nuclei isolation from influenza virus-infected chick fibroblast cells are characterized comparatively. The purity of the nuclear preparations was evaluated by hemagglutinin determination in them in hemagglutination test or hemagglutinin and membrane protein determination by polyacrylamide gel electrophoresis of labeled proteins. The purest nuclei were prepared by the method using citric acid--MgCl2--triton X-100.

[Synthesis of virus-specific proteins in a mixed infection caused by various strains of influenza virus A and B]. / Sintez virusspetsificheskikh belkov pri smeshannoi infektsii, vyzvannoi razlichnymi shtammami virusa grippa A i B.

Mixed infection produced by different strains of influenza virus was studied. Both laboratory and epidemic strains as well as attenuated vaccine strains were used. Simultaneous double infection of MDCK cells with different combinations of influenza A and B strains led to manifested interference accompanied by phenotypic mixing. In the cells infected with influenza A and B viruses the major virus-specific proteins of both types were found, their rate of synthesis was, however, decreased as compared to that in the course of single infection. The inhibition was reciprocal and differentiated: the synthesis of NP and HA proteins was inhibited stronger than that of NS 1 protein. Homotypic double infection with influenza A strains also led to a decrease in virus-specific protein synthesis. The analysis of virus progeny revealed phenotypic mixing of HA or complete inhibition of formation of virions carrying one of the hemagglutinin types (e.g. type A hemagglutinin in heterotypic double infection). The extent of interference and phenotypic mixing depended on the multiplicity of infection.

[Properties of influenza virus isolated from the bodies of mice at different stages of experimental influenza]. / Svoistva virusov grippa, vydelennykh iz organizma myshei na raznykh stadiiakh éksperimental'noi grippoznoi infektsii.

The results of the study of persistent influenza infection in S57BL mice developing after inoculation with influenza virus enriched with defective-interfering (DI) particles are presented. Regular isolation of the virus from lung tissues of the infected animals for 45 days after infection was observed. At later intervals after infection (2-8 months), the lungs and spleens yielded 8 virus strains differing from the original by their pathogenicity for mice, and thermostability of hemagglutinin. Examinations by gel electrophoresis of a strain isolated 6 months after inoculation revealed changes in the mobility of M and NS proteins which could produce some phenotypic changes of the virus in the course of persistent infection.

[Immunological analysis of the surface components of the influenza virus similar to the serovariant A (Hsw1N1) isolated in Alma-Ata 1984-1985]. / Immunologicheskii analiz poverkhnostnykh komponentov virusa grippa, podobnogo serovariantu A (Hsw1N1) izolirovannogo v Alma-Ate v 1984-1985 gg.

The results of immunological analysis of the antigenic structure of hemagglutinin and neuraminidase of influenza A (serovariant Hsw 1) isolates recovered in Alma-Ata in 1984-1985 are presented. By means of specific adsorption and immunoprecipitation the antigenic structure of new isolates was shown to be very similar to that of the A/swine/Iowa/15/30 strain.

[Comparative study of the effectiveness of the purification and concentration of herpes simplex virus types 1 and 2]. / Sravnitel'noe izuchenie éffektivnosti ochistki i kontsentratsii virusa prostogo gerpesa tipov 1 i 2.

The results of comparative studies on concentration and purification of herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2) by ficol density gradient centrifugation are presented. A two-phase distribution of extracellular HSV was established in phycol density gradient centrifugation: in zones with density of 1.110-1.114 and 1.088-1.085 g/ml. The effectiveness of purification of HSV preparations recovered from the corresponding gradient zones was determined by electron microscopy and quantitation of the contaminating cellular (radioactive) proteins in virus purification from a mixture of the culture fluid from infected cultures and the culture fluid from uninfected labeled human embryo skin-muscle tissue cultures (HESM) and a mixture of unlabeled extracellular HSV and a homogenate of labeled uninfected HESM cultures. In HSV purification from the virus-containing culture fluid the amount of cellular proteins was shown to decrease 500-fold in 150-fold virus concentration. In purification of extracellular HSV from the mixture with cell homogenate the amount of cellular proteins decreased 70- and 100-fold for HSV-2 and HSV-1, respectively. The infectious virus yield in phycol gradient centrifugation of a precipitate obtained by the addition of polyethylene glycol-6000 to the culture fluid for HSV-1 was 34.7% (in titrations in HESM cultures) and 38.4% (by intracerebral inoculation of mice weighing 5-6 g), and for HSV-2 20.2% and 26.3%, respectively.

[Comparative analysis of the virus-specific proteins of cells infected with untypable herpes simplex virus strains]. / Sravnitel'nyi analiz virusspetsificheskikh belkov zarazhennykh netipiruiushchimisia shtammami virusa prostogo gerpesa kletok.

Herpes simplex viruses of the so-called intermediate types were typed by analysis of virus-specific proteins of the infected cells. The results obtained correlate well with the results of typing of these strains by DNA analysis using restriction endonucleases. Strain differences of virus-specific proteins of herpes simplex virus of both types were established.

[Infectivity of influenza viruses for an organ culture of human embryonic trachea and the change in this trait in recombination]. / Infektsionnost' virusov grippa dlia organnoi kul'tury trakhei émbriona cheloveka i izmenenie dannogo priznaka pri rekombinatsii.

The infecting and reproduction activity of epidemic and vaccine strains of influenza virus as well as their recombinants was studied in human embryo trachea culture. At a certain combination of genes the recombinants showed new qualities: increased tropism to cells of the human upper respiratory tract and intensified virus reproduction in these cells. Of special interest was a recombinant containing the inner proteins of A/Leningrad/9/46 (H0N1) virus and external proteins of A/Brazil/11/78 (H1N1) virus. A possible association of the genes of the internal proteins of influenza A/Leningrad/9/46 virus with the intensity of reproduction, and of the genes of surface glycoproteins with the species specificity of this recombinant is discussed.

[Antigenic recombinants of human influenza viruses with viruses isolated from wild birds]. / Antigennye rekombinanty virusov grippa cheloveka s virusami, vydelennymi ot dikikh ptits.

Antigenic recombinants obtained by crossing of different human and animal influenza viruses were studied for some genetic markers and specific proteins in the resulting recombinants were analyses. In a number of cases the origin of inner virion proteins (NP and M) from one or the other parent and nonstructural NS proteins was established.

[Genome of defective interfering influenza virus particles: multiple reactivation of "incomplete" virus detectable by counting hemadsorbing cells]. / Genom defektnykh interferiuruiushchikh chastits virusa grippa: mnozhestvennaia reaktivatsiia "neopolnogo" virusa, vyiavliaemaia metodom podscheta gemadsorbiuruiushchikh kletok.

Gel electrophoresis reveals additional segments of low molecular mass in RNA preparations of "incomplete" (produced by passages of undiluted material according to von Magnus) influenza virus which are lacking in RNA of the standard virus. When MDCK cells are inoculated with the "incomplete" virus, synthesis of virus-specific proteins is observed but the pattern of relationships between the intensity of the synthesis and multiplicity of infection is different from that of the standard virus. Quantitative determination of infectivity by counting of haemadsorbing cells demonston the dilution of the "incomplete" virus in contrast to the linear dependence in infection with the standard virus. Neither the virus-specific protein synthesis nor cell conversion into the haemadsorbing state can be due to the admixture of infectious particles in "incomplete" virus preparations and indicate an effect of the type of multiple activation of virus genome expression.