Antigenic Architecture of the H7N2 Influenza Virus Hemagglutinin Belonging to the North American Lineage.

The North American low pathogenic H7N2 avian influenza A viruses, which lack the 220-loop in the hemagglutinin (HA), possess dual receptor specificity for avian- and human-like receptors. The purpose of this work was to determine which amino acid substitutions in HA affect viral antigenic and phenotypic properties that may be important for virus evolution. By obtaining escape mutants under the immune pressure of treatment with monoclonal antibodies, antigenically important amino acids were determined to be at positions 125, 135, 157, 160, 198, 200, and 275 (H3 numbering).

Determination of cold-adapted influenza virus (Orthomyxoviridae: ) polymerase activity by the minigenome method with a fluorescent protein.

Introduction: Polymerase proteins PB1 and PB2 determine the cold-adapted phenotype of the influenza virus A/Krasnodar/101/35/59 (H2N2), as was shown earlier.

Objective: The development of the reporter construct to determine the activity of viral polymerase at 33 and 37 °C using the minigenome method.

Materials And Methods: Co-transfection of Cos-1 cells with pHW2000 plasmids expressing viral polymerase proteins PB1, PB2, PA, NP (minigenome) and reporter construct.

Evolutionary Dynamics of Avian Influenza Viruses Isolated from Wild Birds in Moscow.

Forty-five strains of AIVs were isolated from wild aquatic birds during their autumn migration through Moscow (Russia). The aim of this work is to study the dynamics of AIV genomes in their natural habitat. Viruses were isolated from fecal sample in embryonated chicken eggs; their complete genomes were sequenced, and a phylogenetic analysis was performed.

Monitoring of Avian Influenza Viruses and Paramyxoviruses in Ponds of Moscow and the Moscow Region.

The ponds of the Moscow region during the autumn migration of birds are a place with large concentrations of mallard ducks, which are the main hosts of avulaviruses (avian paramyxoviruses) and influenza A viruses (IAV). The purpose of this study was the determination of the biological diversity of IAV and avulaviruses isolated from mallards in Moscow's ponds. A phylogenetic analysis of IAV was performed based on complete genome sequencing, and virus genomic reassortment in nature was studied.

Molecular Characteristics, Receptor Specificity, and Pathogenicity of Avian Influenza Viruses Isolated from Wild Ducks in Russia.

Avian influenza viruses (AIV) of wild ducks are known to be able to sporadically infect domestic birds and spread along poultry. Regular surveillance of AIV in the wild is needed to prepare for potential outbreaks. During long-year monitoring, 46 strains of AIV were isolated from gulls and mallards in Moscow ponds and completely sequenced.

Substitution Arg140Gly in Hemagglutinin Reduced the Virulence of Highly Pathogenic Avian Influenza Virus H7N1.

The H7 subtype of avian influenza viruses (AIV) stands out among other AIV. The H7 viruses circulate in ducks, poultry and equines and have repeatedly caused outbreaks of disease in humans. The laboratory strain A/chicken/Rostock/R0p/1934 (H7N1) (R0p), which was previously derived from the highly pathogenic strain A/FPV/Rostock/1934 (H7N1), was studied in this work to ascertain its biological property, genome stability and virulent changing mechanism.

Diversity and Reassortment Rate of Influenza A Viruses in Wild Ducks and Gulls.

Influenza A viruses (IAVs) evolve via point mutations and reassortment of viral gene segments. The patterns of reassortment in different host species differ considerably. We investigated the genetic diversity of IAVs in wild ducks and compared it with the viral diversity in gulls.

The Effect of I155T, K156Q, K156E and N186K Mutations in Hemagglutinin on the Virulence and Reproduction of Influenza A/H5N1 Viruses.

The continued circulation of influenza A virus subtype H5 may cause the emergence of new potential pandemic virus variants, which can be transmitted from person to person. The occurrence of such variants is mainly related to mutations in hemagglutinin (HA). Previously we discovered mutations in H5N1 influenza virus hemagglutinin, which contributes to virus immune evasion.

[The Effect of I155T, K156Q, K156E and N186K Mutations in Hemagglutinin on the Virulence and Reproduction of Influenza A/H5N1 Viruses].

The continued circulation of influenza A virus subtype H5 may cause the emergence of new potential pandemic virus variants, which can be transmitted from person to person. The occurrence of such variants is mainly related to mutations in hemagglutinin (HA). Previously we discovered mutations in H5N1 influenza virus hemagglutinin, which contributes to virus immune evasion.

Variability of nonpathogenic influenza virus H5N3 under immune pressure.

Mutations arising in influenza viruses that have undergone immune pressure may promote a successful spread of mutants in nature. In order to evaluate the variability of nonpathogenic influenza virus A/duck/Moscow/4182-C/2010(H5N3) and to determine the common epitopes between it and highly pathogenic H5N1 avian influenza viruses (HPAIV), a set of escape mutants was selected due to action of MABs specific against A/chicken/Pennsylvania/8125/83(H5N2), A/Vietnam/1203/04(H5N1) and A/duck/Novosibirsk/56/05(H5N1) viruses. The complete genomes of escape mutants were sequenced and amino acid point mutations were determined in HA, NA, PA, PB1, PB2, M1, M2, and NP proteins.

[Development of entrepreneurship in the field of medical care based on the franchising model].

The article deals with the issues of functioning of Russian medical centers on the terms of franchising, relevant for the development of entrepreneurship in the field of medical care. Over the past few years, the number of private medical organizations in the Russian Federation has been growing, and the number of business representatives who want to participate in the development of entrepreneurship and conduct socially significant activities in the field of medical care has been increasing. The search for the most effective ways to establish and develop a business in the medical industry contributes to the growing interest in the franchise model, which allows you to expand the scale of your business.

[Three Mutations in the Stalk Region of Hemagglutinin Affect the pH of Fusion and Pathogenicity of H5N1 Influenza Virus].

Previously, an attenuated variant Ku/at was obtained from the highly pathogenic avian influenza virus A/chicken/Kurgan/3/2005 (H5N1) by a reverse selection method aimed at increasing the virus resistance to a proteolytic cleavage and acidic pH values. In the Ku/at, 10 mutations in proteins PB2, PB1, HA, NA, and NS1 occurred. In comparison with the parental strain, the pH of the conformational transition of the viral glycoprotein hemagglutinin (HA) and virulence for mice and chickens have decreased in an attenuated variant.

[Mutations in Hemagglutinin and Polymerase Alter the Virulence of Pandemic A(H1N1) Influenza Virus].

To study the pathogenicity factors of the pandemic A(H1N1) influenza virus, a number of mutant variants of the A/Hamburg/5/2009 (H1N1)pdm09 strain were obtained through passage in chicken embryos, mouse lungs, and MDCK cell culture. After 17 lung-to-lung passages of the A/Hamburg/5/2009 in mice, the minimum lethal dose of the derived variant decreased by five orders of magnitude compared to that of the parental virus. This variant differed from the original virus by nine amino acid residues in the following viral proteins: hemagglutinin (HA), neuraminidase (NA), and components of the polymerase complex.

Receptor-binding properties of influenza viruses isolated from gulls.

Ducks, gulls and shorebirds represent the major hosts of influenza A viruses (IAVs) in nature, but distinctions of IAVs in different birds are not well defined. Here we characterized the receptor specificity of gull IAVs with HA subtypes H4, H6, H14, H13 and H16 using synthetic sialylglycopolymers. In contrast to duck IAVs, gull IAVs efficiently bound to fucosylated receptors and often preferred sulfated and non-sulfated receptors with Galβ1-4GlcNAc cores over the counterparts with Galβ1-3GlcNAc cores.

Immunization of Domestic Ducks with Live Nonpathogenic H5N3 Influenza Virus Prevents Shedding and Transmission of Highly Pathogenic H5N1 Virus to Chickens.

Wild ducks are known to be able to carry avian influenza viruses over long distances and infect domestic ducks, which in their turn infect domestic chickens. Therefore, prevention of virus transmission between ducks and chickens is important to control the spread of avian influenza. Here we used a low pathogenic wild aquatic bird virus A/duck/Moscow/4182/2010 (H5N3) for prevention of highly pathogenic avian influenza virus (HPAIV) transmission between ducks and chickens.

[Changes in the phenotypic properties of highly pathogenic influenza A virus of H5N1 subtype induced by N186I and N186T point mutations in hemagglutinin].

The change in the phenotypic properties resulting from amino acid substitutions in the hemagglutinin (HA) molecule is an important link in the evolutionary process of influenza viruses. It is believed to be one of the mechanisms of the emergence of highly pathogenic strains of influenza A viruses, including subtype H5N1. Using the site-directed mutagenesis, we introduced mutations in the HA gene of the H5N1 subtype of influenza A virus.

Immunization with live nonpathogenic H5N3 duck influenza virus protects chickens against highly pathogenic H5N1 virus.

Development of an effective, broadly-active and safe vaccine for protection of poultry from H5N1 highly pathogenic avian influenza viruses (HPAIVs) remains an important practical goal. In this study we used a low pathogenic wild aquatic bird virus isolate А/duck/Moscow/4182/2010 (H5N3) (dk/4182) as a live candidate vaccine. We compared this virus with four live 1:7 reassortant anti-H5N1 candidate vaccine viruses with modified hemagglutinin from either A/Vietnam/1203/04 (H5N1) or A/Kurgan/3/05 (H5N1) and the rest of the genes from either H2N2 cold-adapted master strain A/Leningrad/134/17/57 (rVN-Len and rKu-Len) or H6N2 virus A/gull/Moscow/3100/2006 (rVN-gull and rKu-gull).

[Testing of apathogenic influenza virus H5N3 as a poultry live vaccine].

Four H5N2 experimental vaccine strains and the apathogenic wild duck H5N3 influenza virus A/duck/ Moscow/4182/2010 (dk/4182) were tested as a live poultry vaccine. Experimental strains had the hemagglutinin of the A/Vietnam/1203/04 strain lacking the polybasic HA cleavage site or the hemagglutinin from attenuated virus (Ku/ at) that was derived from the highly pathogenic influenza virus A/chicken/Kurgan/3/2005 (H5N1). The hemagglutinin of the Ku-at has the amino acid substitutions Asp54/Asn and Lys222/Thr in HA1 and Val48/Ile and Lys131/Thr in HA2, while maintaining the polybasic HA cleavage site at an invariable level.

Epizootic of vesicular disease in pigs caused by coxsackievirus B4 in the Soviet Union in 1975.

Swine vesicular disease virus (SVDV) emerged around 1960 from a human enterovirus ancestor, coxsackievirus B5 (CVB5), and caused a series of epizootics in Europe and Asia. We characterized a coxsackievirus B4 strain that caused an epizootic involving 24 488 pigs in the Soviet Union in 1975. Phylogenetic evidence suggested that the swine virus emerged from a human ancestor between 1945 and 1975, almost simultaneously with the transfer of CVB5.

[New genotype of the sacbrood virus of the honeybee Apis mellifera].

The sacbrood virus (SBV) leads to death of honeybee larvae. Until now, there were known three SBV genotypes: European, Asian, and South African (E. Grabensteiner et al.

[The generation and characteristics of reassortant influenza A virus with H5 hemagglutinin and other genes from the apathogenic virus H6N2].

The experimental reassortant vaccine strain VN-gull (H5N2) containing H5 hemagglutinin (HA) with a removed polybasic site in the connecting peptide and other genes from the apathogenic H6N2 virus A/gull/Moscow/3100/2006 (gull/M) was obtained using a two-step protocol. At Step 1, the reassortant with HA of A/Vietnam/1203/04-PR8/ CDC-RG and other genes from cold-adapted A/Leningrad/17/47 (VN-Len) viruses was generated due to selection with antibody to H2N2 at 26 degrees C. At Step 2, the reassortant VN-gull was obtained by replacing all genes from Len with those from gull/M due to selection with antibody to H6N2 at 39 degrees C.

Comparative safety, immunogenicity, and efficacy of several anti-H5N1 influenza experimental vaccines in a mouse and chicken models (Testing of killed and live H5 vaccine).

Objective: Parallel testing of inactivated (split and whole virion) and live vaccine was conducted to compare the immunogenicity and protective efficacy against homologous and heterosubtypic challenge by H5N1 highly pathogenic avian influenza virus.

Method: Four experimental live vaccines based on two H5N1 influenza virus strains were tested; two of them had hemagglutinin (HA) of A/Vietnam/1203/04 strain lacking the polybasic HA cleavage site, and two others had hemagglutinins from attenuated H5N1 virus A/Chicken/Kurgan/3/05, with amino acid substitutions of Asp54/Asn and Lys222/Thr in HA1 and Val48/Ile and Lys131/Thr in HA2 while maintaining the polybasic HA cleavage site. The neuraminidase and non-glycoprotein genes of the experimental live vaccines were from H2N2 cold-adapted master strain A/Leningrad/134/17/57 (VN-Len and Ku-Len) or from the apathogenic H6N2 virus A/Gull/Moscow/3100/2006 (VN-Gull and Ku-Gull).

[A/H13 and A/H16 influenza viruses: different lines of one precursors].

Analysis of the data of annual (1980-2005) monitorings of influenza A viruses in the North Caspian Sea basin and the Volga river delta, as well as the primary hemagglutinin structure of isolates of different years revealed the circulation of A/H13 and A/H16 viruses among gulls since 1976. Phylogenetic analysis revealed 3 significantly different evolutionary lines: an American line, a European line, and a line comprising the isolates from America and Eurasia. The H13N6 and H16N3 viruses isolated in Russia replicated in the respiratory and intestinal tracts of ducks and induced the production of antibodies; the H16N3 viruses induced the antibodies neutralizing viruses of subtype H16 only.

[The study of the nonpathogenic influenza virus A/gull/Moscow/3100/2006 (H6N2) isolated in Moscow].

The influenza virus A/gull/Moscow/3100/2006 (H6N2) was isolated from gull feces within the precincts of Moscow in autumn 2006. The nucleotide sequence of the complete genome (GenBank, EU152234-EU152241) and genotype (K, G, D, 6B, F, 2D, F, 1E) for this virus were determined. Phylogenetic analysis suggests that the H6N2 virus derived by numerous reassortment between viruses that have been circulating among different birds in Europe since 1999 and in South-East Asia (NA gene) for last years.

[Infection of pigs with influenza A/H4 and A/H5 viruses isolated from wild birds on the territory of Russia].

Pigs were intranasally infected with avian influenza A/H5 (H5N1, H5N3) and A/H4 (H4N6, H4N8) viruses in mono- and coinfection. Infection with both apathogenic and pathogenic strains caused no clinical manifestations. A virus and/or fragments of its genome retained in nasopharyngeal fluid as long as 6-8 days after infection.