Conjugates of betulin and betulinic and betulonic acids with 2-aminoethane- and N-methyl-2-aminoethanesulfonic acids were synthesized for the first time and were interesting as potential biologically active compounds. Experiments in vitro in MDCK cell culture using the MTT assay found that betulin and betulinic-acid derivatives with aminoethanesulfonic acid bound to triterpene C-3 or C-28 through an ester linker were less toxic than the native compounds.

Purpose of the study: study of the circulation, isolation and antigenic analysis of influenza viruses A and B in St.-Petersburg in the children aged 0–18 in the seasons 2013–2015.Materials: nasal swabs from children-inpatients from Saint-Petersburg.Methods: virus isolation in MDCK cell culture and chicken embryos, antigenic analysis with the hemagglutination inhibition (HAI) test with the set of hyper-immune rat antisera to the epidemic and reference strains, antigenic cartography.Results: The epidemic seasons 2013–2015 were characterized by the co-circulation in children in St.-Petersburg of influenza sub-types А(H1N1)pdm09, A(H3N2), and B of Yamagata lineage (B yam). In the season 2014–2015 the low activity of epidemic process was observed with the predominant sub-type A(H3N2) and in the next season – 2014–2015 with the more pronounced epidemic activity – the pre-dominance of B yam viruses. Antigenic analysis of influenza viruses А(H1N1)pdm09 which circulated in children revealed their antigenic homogeneity and full correspondence with vaccine strain A/California/07/09. As for А(H3N2) viruses, two antigenic groups were established: strains similar to A/St.-Petersburg/80/14 (sub-clade 3C.2a) and strains similar to A/Switzerland/9715293/13 (sub-clade 3C.3a). А(Н3N2) strains of the season 2013-2014 were similar to the vaccine strain. However isolates of the season 2014-2015 did not fit to the vaccine strain because in the children were predominant strains similar to the evolution branch A/St.-Petersburg/80/14 while according the WHO recommendations the influenza vaccine contained the strain A/Texas/50/12. Antigenic analysis of influenza viruses B showed their homogeneity and all they were B/Phuket/3073/13-like. Influenza strains B also incompletely corresponded to the vaccine strain – B/Massachusetts/2/12 belonging to the different genetic sub-clade. That might be the reason of enhanced morbidity of children with influenza B in the last season.Conclusion: The obtained results stress the urgency for the wide coverage of human population with the epidemic studies, virus isolation in different time periods and geographic regions and their etiological studies with the modern techniques. Only in these conditions we can assure high efficiency of flu seasonal vaccines.

Influenza A virus is a major cause of morbidity and mortality worldwide. There is a large knowledge base on the immune response to influenza. However, few studies have focused on global gene expression in immune cells after antigenic challenge. A better understanding of the host immune response is required for the development of more efficient means of prevention and treatment of influenza. In this study, global gene expression in peripheral blood mononuclear cells (PBMCs) after influenza immunization was analyzed. The differential gene expression in antigen-stimulated and non-stimulated PBMCs was determined by cDNA microarrays. To determine whether a specific gene profile was present during a proliferative memory cell response to influenza antigens, gene expression in response to PHA was compared with antigen-stimulated PBMCs. PHA induced the upregulation of 201 genes while influenza virus antigen upregulated more than triple that is 630 genes out of 1700 genes analyzed. Both influenza antigen and PHA commonly upregulated 138 genes. Interferon (IFN)-related genes were induced by influenza but not by PHA. The interferon-gamma induced protein precursor 10 (IP-10) was upregulated 27-fold while the interferon-induced 54 kDa protein exhibited a 13-fold increase. The following gene families were also selectively upregulated by influenza antigens: complement ligands and receptors, T cell activation genes, growth factors, genes related to antigen processing and inflammatory responses. With PHA, the genes TNF-R, CTSG, CD3 delta, C8B, CRF1 and CCR2 had higher expression compared with the viral antigen stimulation. Neutrophil defensins alpha-1 and two C–C chemokines, proteins MIP-1-beta and MIP-4, were among the genes upregulated by both PHA and influenza antigens. The results suggest that interferon-induced genes are one of the main transcriptional targets during the immune response to influenza virus.

There are presented data of Federal Influenza Center of Russia on morbidity of influenza, intensity, duration, geographical spread of epidemic, recorded lethal outcomes with laboratory-confirmed diagnosis "influenza" in the season of 2014-2015. The epidemic in this season was more intensive in character in comparison to the previous season according to most of the indices. Main etiologic agents were influenza B - 50,6 % of isolated strains, the portion of influenza A(H3N2) viruses accounted for 45 % of isolates and pandemic influenza 2009 virus was revealed only in 4,35 % of studied clinical materials. Incomplete compliance of influenza vaccine for the component A (H3N2), observed in the world in 2015, and especially the further evolution of this group of viruses in the current season demonstrate the importance of the widest possible coverage by epidemiological studies, isolation of the virus in different periods of the epidemic season in different geographical regions and etiological analysis of them with the use of modern methods for the increase of the efficacy of vaccination

The present study describes etiological structure of population of influenza viruses that circulated in Russian Federation in epidemic season 2013 - 2014. It was shown that from 495 isolates influenza A(H1N1)pdm09 viruses comprise 46.3%, influenza A(H3N2) - 44.2% and influenza B - 9.5% with domination of Yamagata lineage. Comparative study of antigenic properties of major influenza surface protein hemagglutinin was conducted based on the results of HI test and three-dimensional antigenic cartography. The correspondence between WHO recommended strains for vaccine composition 2013 - 2014 and Russian strains of the analyzed period was shown. Quantitative analysis of enzyme activity of the second surface influenza protein - neuraminidase - for 203 influenza strains differing in year of isolation, antigenic composition and host specificity showed that the highest activity was registered for the neuraminidase of A(H5N1) influenza viruses. In general, the activity of N1 neuraminidase was higher than that of N2 subtype, but sufficient individual variation of NA activity within the subtype could be registered.

Flu monitoring was carried out in children’s general hospital in St. Petersburg within three epidemic seasons (2010–2011, 2011–2012 and 2012–2013). 1916 patients under the age of 18 years were examined with the complex of virologic tests . The natural decreasing of flu incidence and predominant diagnosing in etiologic structure one of the virus serotypes [in the first A(H1N1)pdm09, in the second — A(H3N2)] have been observed during the first two years after a pandemic. In the third season restoration of the main characteristics of epidemic flu situation were detected: polietiology with annual change of serotypes proportions, late start (winter and spring), majority of younger children among hospitalaized patients and a mild course of disease. The most probable candidates [viruses of a subtype A(H3N2)] are revealed as a causal factor of significant increasing of disease incidence with the severe forms in the near future. Laboratory data were confirmed by increase in frequency of the complicated by pneumonia ARI at hospitalized patients during the periods of their maximum registration. All isolates received during the study were corresponded to the referens-strains included in vaccines. Thus, timely and appropriate vaccination during the studied period had to become an effective protection against a flu.

Flu monitoring was carried out in children’s general hospital in St. Petersburg within three epidemic seasons (2010–2011, 2011–2012 and 2012–2013). 1916 patients under the age of 18 years were examined with the complex of virologic tests . The natural decreasing of flu incidence and predominant diagnosing in etiologic structure one of the virus serotypes [in the first A(H1N1)pdm09, in the second — A(H3N2)] have been observed during the first two years after a pandemic. In the third season restoration of the main characteristics of epidemic flu situation were detected: polietiology with annual change of serotypes proportions, late start (winter and spring), majority of younger children among hospitalaized patients and a mild course of disease. The most probable candidates [viruses of a subtype A(H3N2)] are revealed as a causal factor of significant increasing of disease incidence with the severe forms in the near future. Laboratory data were confirmed by increase in frequency of the complicated by pneumonia ARI at hospitalized patients during the periods of their maximum registration. All isolates received during the study were corresponded to the referens-strains included in vaccines. Thus, timely and appropriate vaccination during the studied period had to become an effective protection against a flu.

Specific traits of influenza B viruses circulation in Russia and worldwide in 2005-2012 were studied and the amount of influenza B viruses in the whole population of influenza viruses isolated in Russia was estimated. The trend toward antigenic drift for both Victoria and Yamagata lineages was characterized. The genetic analysis revealed amino acid changes that influenced the antigenic properties of the viruses. The match of the epidemic isolates and vaccine strains was corroborated.

The basic trends in the evolution of influenza A and B in the Russian Federation during the epidemic seasons of 2006-2009 were studied on the basis of an antigenic analysis of 1774 Influenza isolated at the Research Institute of Influenza (RII), North-Western Branch, Russian Academy of Medical Sciences, and sent from resting bases (the regional centers of the Russian Inspectorate for the Protection of Consumer Rights and Human Welfare, which collaborate with the RII). Although the trends in the substitution of representative strains generally coincide with the world patterns, the authors revealed some specific features of the antigenic drift of influenza viruses in the Russian Federation and regional varieties. Data on some biological properties and those of the antigenic analysis of the first pandemic influenza A(H1NI)v strains isolated at the RII from Saint Petersburg patients in July-August 2009 are also given in the paper.

In the second half of 2005, a large-scale outbreak of influenza in poultry and wild birds was caused by a highly pathogenic H5N1 influenza virus in Russia. The level of pathogenicity is a polygenic trait, and most individual genes contribute to the influenza A virus pathogenicity in birds, animals, and humans. The full-length nucleotide sequences were determined for H5N1 strains isolated in the Kurgan region (Western Siberia). The structure of viral proteins was analyzed using the deduced amino acid sequences. The receptor-binding site of hemagglutinin (HA) in strains A/chicken/Kurgan/05/2005 and A/duck/Kurgan/08/2005 was typical for avian influenza viruses and contained Glu and Gly at positions 226 and 228, respectively. The structure of the basic amino acid cluster located within the HA cleavage site was identical in all isolates: QGERRRKKR. According to the neuraminidase structure, all H5N1 isolates from the Kurgan region were assigned to the Z genotype. Amino acid residues typical for the avian influenza virus were revealed in 30 out of 32 positions of M1, M2, NP, PA, and PB2, determining the host range specificity. One of the strains contained Lys at position 627 of PB2. Isolates from the Kurgan region were shown to have a remantadine-sensitive genotype. Both strains contained Glu at position 92 of NS1, indicating that the virus is interferon-resistant. Phylogenetic analysis related the Kurgan isolates to subclade 2 of clade 2 of highly pathogenic H5N1 influenza viruses.

Influenza epidemic events in Russia from 1998 up to 2005 were associated with the circulation of influenza A (H3N2), A (H1N1) and B viruses. The antigenic analysis revealed that the evolution of A (H3N2) viruses proceeded as following: A/Sydney/05/97→A/Panama/2007/99→A/Fujian/411/02→A/Wellington/01/04; A (H1N1) viruses: A/Bayern/07/95→A/Bejing/262/95→A/New Caledonia/20/99; B viruses evolved as two distinct lineages: Victoria- and Yamagata-like viruses. Our results have shown that the evolution in Russia coincided the World trends.

Influenza A(H1N1), A(H3N2), and B viruses circulated in Russia during 1993–2003. In those years, A(H1N1) viruses caused four epidemics, A(H3N2) viruses caused eight epidemics, and B viruses caused seven epidemics. Strains similar to A/Beijing/262/95 were first isolated in Russia in 1998 and B/Victoria/2/87-like strains in 2003. The study of antigenic and biological properties of epidemic A(H3N2) strains showed their hemagglutinin heterogeneity.

The etiological structure of influenza-like was analyzed in the population in cities and towns and in Russia as a whole in November 1998 to April 1999 by the findings of immunofluorescence and serological surveys of patients with acute respiratory viral infections (ARVI). By the results of both tests, the proportion of the incidence of influenza A (H3N2) was largest, the decreasing order in their significance was as follows: adenoviruses, type 3 parainfluenza virus, RSV, influenza B virus, influenza A(H1N1), types 2 and 1 parainfluenza virus. All influenza viruses A(H1N1) were isolated in Samara in February 1999. Three of them were similar to the reference strain A/Johannesburg/82/96 in antigenic properties, two strains appeared to be its drift variants. No A/Beijing/262/95 (H1N1)-like viruses recommended for incorporation as part of vaccines were detected. All influenza A(H3N2) viruses were drift variants of strain A/Sydney/05/97, and all influenza B viruses were similar to the reference strain B/Harbin/07/94 in antigenic structure.

The antigenic properties of 51 strains of influenza virus A(H1N1), isolated in different cities of Russia during the epidemic of 1998, were studied. Most of these strains (49) proved to be similar to virus A/Bern/07/95 in the antigenic structure of hemagglutinin, but 2 strains isolated in Ulan-Ude were found to be closely related to new antigenic variants of this virus: A/Beijing/262/95 and A/Fukuoka/c7/98. The analysis of the antigenic structure of influenza-like diseases (ILD) in different cities of Russia revealed that adenoviruses causing up to 10.9-14.6% of all acute respiratory virus infections dominated at the pre- and post-epidemic periods. RS-viruses, parainfluenza viruses of types 2 and 3 circulated during the whole season (their proportion was 5.1-6.6%). The intensity of the circulation of influenza viruses A(H1N1) and A(H3N2) increased, starting from January, and continued till April 1998; its peak was observed in February-March in most of the cities of Russia (up to 37.5-41.6% according to the results of immunofluorescent diagnostics and 53-73% of ILD according to the results of the hemagglutination inhibition test). The occurrence of influenza B during this season was very low.