The investigation of the dynamics of changes in neutralizing antibody titers against type 5 adenovirus in the context of vaccination against a new coronavirus infection.

This research focuses on analyzing the dynamics of neutralizing antibody (nAbs) titers against type 5 adenovirus (Ad5) in the adult population of Russia following vaccination against the novel coronavirus infection with recombinant adenovirus type-5 COVID-19 vaccine (CanSino Biologics, China). The impact of the Ad5 vector on nAb titers was investigated using 302 blood serum samples from individuals who received a single dose of the Ad5-nCoV vector vaccine. The research revealed that 33.8% of adults in Russia had pre-existing anti-Ad5 nAbs before the pandemic. Notably, 40% of vaccinated individuals did not exhibit an increase in nAbs titers upon receiving the Ad5-based vaccine. However, in the group with no or low titers of anti-Ad5 nAbs (1:10-1:40), a significant 8-16-fold increase in nAb titers to Ad5 was observed.

CHRONIC HEPATITIS WITH DOUBLE B/C INFECTION: VIROLOGICAL, CLINICAL, MORPHOLOGICAL CHARACTERISTICS.

AIM: To estimate the r, virological and clinical characteristics of chronic viral hepatitis (CVH) with double B/C infection. MATERIALS AND METHODS: We examined 282 patients with CVH. Genomes of hepatitis B virus (HBV) and hepatitis C virus (HCV) were studied by PCR in blood and liver (AmpliSens HBV and Amplisens HCV Russia), nuclear proteins (HBcorAg HBV and NS3 HCV) were determined by immunohistochemical method (Novocastra, UK), HBVgenome was sequenced by the Sanger method using ABI prism BigDye Terminator v3.1 kits and ABIPRISM 3100 analyzer (AppliedBiosystems, USA). Indices of histological activity (HAI), fibrosis, and portal vein (PV) congestion index (CI) were calculated by formula CI=SBB/LB V where S is P V cross section area in cm2 and LB V - linear blood flow velocity in cm/s (Vivid Pro- 7 apparatus, USA). RESULTS: CVH with double B/C infection was diagnosed in 85 (30.1%) patients including 44.7% with viral genomes and proteins in the live; 42.4% with HCVviremia, and 12.9% with HBJV/HCVviremia. Maximum CVH activity was documented in patients with latent HBV/HCVviremia (ALT 157.2±59.2 U/, HAI 11.6±1.3,fibrosis 2.8±0.7, C1 0.059±0.005); it was minimal inpatients.without viremia (Alt 76.25±63.0 U/I, HAI 6.7+-0.6,fibrosis 1.7±0.5, CI 0.042±0.001;p <0.05). Patients with latent HBV infection had precore/ore and pres/s mutations in HBVgenome and cytoplasmic localization ofHBcorAg. CONCLUSION: Double B/C infection was diagnosed in 30.1% of the patients with CVH dominated by HCV Patients with latent HBVhadprecore/ore and pres/s mutations. The highest intensity of hepatic cellular inflamation,fibrosis, and PV congestion was associated with HBV/HCV viremia and the lowest with intrahepatic localization of both viruses.

[Epitope analysis of the hemagglutinin molecule of the Victoria lineage influenza B viruses].

A panel of five monoclonal antibodies (MAbs) to the HA1 molecule of the influenza B virus of the Victorian lineage with high virus-neutralizing activity was developed. For identification of the virus neutralizing epitopes in HA1 escape mutants (EM) of the influenza BIShandong/07/97 and B/Malaysia/2506/04 virus were selected using virus- neutralizing antibodies (MAbs). Three EMs had single, two--double and one--triple amino acid substitutions (AAS) in HA1 (H122N, A202E, K203T, K2031, K203N or A317V). In addition, AAS N197S was detected in three EMs. A correlation of AAS identified with peculiarities of interaction of EMs with Mabs was discussed.

[Characterization of cold-adapted influenza strain A/HongKong/1/68/162/35 as a potential donor of attenuation and high reproduction].

Live and inactivated vaccines are currently produced using virus reassortants originating from various gene donors of internal proteins. Based on the pandemic virus A/Hong Kong/1/68 (H3N2), a cold-adapted thermo-sensitive strain A/Hong Kong/1/68/162/35 was generated. It is distinguished for its high reproductive capacity (9-9.5 lg EID50), and hemagglutinating activity (1:1024-1:2048). The strain has ts and ca phenotype: reproductive capacity at t = 39 degrees C is 1.0 lg EID50; at t = 26 degrees C, 8.5 lg EID50. A total of 16 mutations have emerged from comprehensive sequencing of the virus genome. Among them 10 mutations were located in the genes of polymerase complex and NP, with respective amino-acid substitutions. The stability of strain characteristics, such as attenuation to humans and high reproductive capacity, were confirmed by repeated sequencing of the genome after tenfold passing of the virus in chicken embryos. Reassortants of the strain A/Hong Kong/1/68/162/35 with the wild-type viruses have inherited useful features of donor virus.

[Evolutionary variability of influenza B viruses in Russian Federation in 2005-2012].

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.

[Development of influenza surveillance in Russia in the system of the WHO national influenza center].

Analysis of development influenza activity season 2010-2011 is presented. Significant participation of influenza A(H1N1)pdm09 virus and influenza B of Victoria lineage virus in the epidemic morbidity structure with minor participation ofA(H3N2) virus was revealed. The influenza viruses isolated in Russia according to antigenic properties were similar to the strains included in the vaccine composition. Drift variants of influenza A(H1N1)pdm09 viruses isolated in Astrakhan and St.-Petersburg were recognized using WHO CC in London as representatives of three new genetic groups.

[Genetic diversity and molecular evolution of the influenza A viruses in Russia during 2006-2012].

The results of molecular genetic analysis of more than 280 strains of influenza A virus subtypes H1N1 and H3N2 circulating in Russia in 2006-2012 are presented. The genetic changes underlying the evolution of the virus strains and sensitivity to antiviral drugs were analyzed. Significant changes in the genetic structure of influenza A viruses circulating in the Russian Federation and their phylogenetic affiliation are shown to occur within the studied period. The studies identifying codons under the positive selection in silico in the genes encoding surface proteins of the influenza virus were demonstrated to be efficient for the analysis of the antigenic drift and direction of evolutionary variability of the influenza viruses.

[H1N1V influenza epidemic of 2009 in Russia].

The paper describes dynamics, distribution and morbidity rate during the 2009 A(H1N1)v influenza epidemic in Russia. The epidemic appears to have been especially severe in the cities of the Far-East and Siberian Federal Districts where the average morbidity rate ranged from 6.4% to 19.2% (mean 10.3%) and the epidemic duration from 7.8 to 8 weeks. In less affected Southern and Central Federal Districts A(H1N1)v influenza occurred in 5.7% of the population. Schoolchildren aged 7-4 years showed the highest morbidity rate of 28.8%. The age group of 18-53 years accounted for 79.4% of the total lethality. Viral isolates were genetically stable and exhibited 98.9% hemagglutnin (HA) homology with reference viruses. None of the strains had an amino acid substitution at position 275 of neuraminidase (NA) responsible for resistance to oseltamivir. Towards the end of the epidemic, the viral population displayed a significant rise in the number of strains containing mutations in 4 genes (4 HA, 2 NA, 2 PB2 and 1 PA mutations respectively). 26.7% of the viral isolates obtained in the end of the epidemic had D222G substitution responsible for tropism of viruses to lung tissues. Epidemiologically, the 2009 A(H1NI)v influenza epidemic is described as moderate based on the absence of pathogenicity determinants typical of both A(H1N1) influenza virus of 1918 and A(H5N1) virus. The paper compares the 2009 epidemic with those caused by A/Honkong/68 and A/USSR/ 90/77 viruses. The necessity of classification for the discrimination between A(H1N1) subtype viruses is emphasized.

[Analysis of pandemic influenza in Russia as a part of the global process based on data of an influenza monitoring reference center].

AIM: Characterization of features of influenza pandemic development in Russia in relation to global process. MATERIALS AND METHODS: Pandemic monitoring was performed by using results of integrative analysis of laboratory diagnostic and population morbidity data from 49 supporting bases of Federal center of influenza from various cities in Russian Federation. Isolation of influenza virus was carried out in MDCK cells and chicken embryos under BSL-3 conditions. Reference virus A/California/07/09 obtained from CDC (Atlanta, USA) and antisera against this strain contained in WHO kit were used for antigenic analysis; rat antisera, new monoclonal antibodies against pandemic influenza virus developed by Research institute of influenza were also used. RESULTS: Based on PCR monitoring during epidemic peak, rate of pandemic influenza identification reached 45-49% of examined patients. About 53% of lethal cases of respiratory infections were caused by pandemic influenza virus, while predominately young people died from pneumonia and acute respiratory distress syndrome. Russian isolates generally were antigenically and genetically similar to the parent pandemic strain--influenza virusA/California/07/09, but contained S203T substitution in hemagglutinin. A number of strains contained D222G mutation that is responsible for the expansion of substrate specificity, as well as strain specific substitutions in hemagglutinin and neuraminidase molecules. The investigated isolates were resistant to remantadin, but sensitive to oseltamivir. CONCLUSION: Due to the formation of population immunity after the end of the first pandemic wave new drift variants of the virus capable of overcoming this formed immunity should be expected that apparently will require the correction of vaccine composition for the 2011 - 2012 season.

[The 2009 pandemic influenza in Russia. I. Diagnosis and molecular biological characteristics of the virus].

The analysis of 1558 clinical samples revealed influenza virus A(H1N1v) RNA in 339 patients with influenza and 163 fatal cases,which was made in May to December 2009. Data on the antigenic properties of more than 250 of pandemic virus strains isolated at the Research Institute of Influenza and the molecular genetic characteristics of 31 strains are presented. All the test isolates were found to have the S203 substitution in hemagglutinin, which was characteristic of one of 5 minor genome A(H1N1v) virus variants found in the United States and Mexico in 2009. All the test strains contain the S31N substitution in the M2 protein, which determines viral resistance to adamantine, and have no H275Y substitution in neuraminidase, which determines oseltamivir resistance. The substitution of amino acid residue of Asp to Gly at position 222 of HA was found in 8 (73%) of 11 isolates from postmortem lung and trachea samples and in 2 (10%) of 20 isolates from nasopharyngeal swabs. The determination of the pathogenic role of this substitution calls for further investigations.

[Preclinical studies of live intranasal H5N1 influenza vaccine with the deleted HS1 gene].

The paper gives the results of evaluating the efficiency of deINS1 pandemic H5N1 vaccine candidate VN1203delNS1 which was constructed by reverse genetics on the basis of influenza virus strain A/Vietnam/1203/04. The safety, immunogenicity and cross-protection of the vaccine strain against different H5N1 virus clades were demonstrated in mouse and macaque models. The results showed the possibility of designing a new-generation replication-deficient intranasal influenza vaccine, by applying an approach to deleting the NS1 pathogenicity factor, an antagonist of the interferon system.

[Formation of antibodies against neuraminidase of A/California/07/2009 (H1N1) influenza virus after immunization with live monovalent influenza vaccine].

AIM: Detection of antibodies against neuraminidase (NA) of A/California/07/2009 (H1N1) influenza virus in blood sera of volunteers after the immunization with live monovalent influenza vaccine (LIV). MATERIALS AND METHODS: Neuraminidase enzyme activity inhibition by antibodies test with reassortant strain A(H7N1) containing NA of pandemic strain was used. Anti-neuraminidase IgG antibodies against whole reassortant virus A(H7N1) and purified NA of A/California/07/2009 (H1N1) strains were determined by enzyme immunoassay (EIA). RESULTS: After two immunizations with LIV of seronegative individuals a 1.5 times mean increase of antibodies against homologous neuraminidase was detected (by hemagglutinin inhibition reaction). The high level of anti-neuraminidase antibodies were detected in individuals that had been naturally infected. A correlation between anti-neuraminidase IgG antibody titers obtained in EIA with whole reassortant virus A(H7N1) and purified protein was demonstrated. CONCLUSION: Modified sialidase activity inhibition method and EIA with reassortant diagnostic strain can be applied to evaluate anti-neuraminidase antibodies.

[Pathogenic aspects of influenza during the epidemics caused by A/H1N1v virus in 2009-2010 according autopsy data].

The paper is based upon the results of clinic-pathological and virological correlations in 29 lethal cases of influenza in Saint-Petersburg and Leningrad region during the epidemics 2009/2010. Immunohistochemical analysis of lungs, heart and brain using monoclonal sera to HA and HP proteins of influenza virus, virological and morphological analysis of experimental influenza in mice infected by A/WSN/33 (HIN1) and A/California/07/09 (H1N1) viruses had been carried out. In the majority of investigated strains was proved the amino acid mutation with replacement D222G. The replication of virus was demonstrated at the late stages of diseases, but the desquamation of respiratory epithelium and cytoproliferative weren't found out. Besides the "influenza cells", previously described by A. V Zinserling the cells with enlarge light nuclei were observed. Patients with influenza died from respiratory distress syndrome with minimal bacterial infection. We've established that H1N1 virus not only damages the cells of respiratory epithelium and alveolar macrophages but it can injure endothelium of different organs and neuroglia. The questions which have to be discussed are listed.

[Molecular characteristic of influenza virus A H5N1 Strains isolated from poultry in Kurgan Region in 2005].

During the latter half of 2005 a widespread outbreak caused by influenza highly pathogenic H5N1 virus among wild and domestic birds occurred in Russia. As pathogenicity level is a polygenic feature and majority of individual genes of influenza A viruses contribute to pathogenicity of influenza viruses to birds, animals and humans. Nucleotide sequencing of the entire genome of influenza H5N1 virus isolates obtained in Kurgan region (Western Siberia) was performed. Structure of viral proteins was analyzed according to the predicted amino acid sequences. HA receptor-binding site of A/chicken/Kurgan/05/2005 and A/duck/Kurgan/08/2005 strains was typical for avian influenza viruses and contained Glu and Gly at positions 226 and 228, respectively. Structure of the cluster of positively charged amino acid residues at the cleavage site was identical for all isolates: QGERRRKKR. According to the data of neuraminidase structure analysis NA of the H5N1 isolates tested was suggested to belong to Z genotype. Amino acid residues typical for birds were revealed in 30 out of 32 positions of M1, M2, NP, PA and PB2 proteins determining host range specificity. One strain isolated in Kurgan contained lysine in position 627 of PB2 protein. Kurgan isolates was shown to have remantadine-sensitive genotype. Glutamic acid was found at position 92 of NS1 protein in both strains indicating virus resistance to interferon. Phylogenetic analyses allowed relating Kurgan isolates to subclade II of clade II of highly pathogenic H5N1 influenza viruses.

[Usage of polymerase chain reaction in complex diagnosis of hepatitis B]. / Primenenie polimeraznoi tsepnoi reaktsii v kompleksnoi diagnostiki gepatita B.

Sera from 926 patients were analyzed by PCR using universal primers to surface gene of hepatitis B virus (HBV). HBV DNA was detected in 195 specimens. There were no serological markers of HBV in 8.2% of these sera, but later they were detected in patients' sera. In patients without HBV DNA in the serum, specific HBV antigens and antibodies were detected in 62%. Only in 14% of them the clinical picture of the disease corresponded to acute viral hepatitis, although the blood for PCR analysis was collected during the late stages of the infection. The rest cases were referred to mixed hepatitis C + D. Comparison of the results of PCR test and detection of serological virus replication markers HBeAg and HBeAb showed the presence of HBV DNA in 28% cases without HBeAg.

[Isolation and cloning of gene for hepatitis delta antigen. The use of recombinant antigen for serodiagnosis of delta infection]. / Vydelenie i klonirovanie gena antigena virusa gepatita del'ta. Ispol'zovanie rekombinantnogo antigena dlia serodiagnostiki del'ta-infektsii.

Hepatitis delta virus antigen was isolated from a patient by reverse transcription and polymerase chain reaction. Gel-purified cDNA was cloned in E. coli expression vectors. High expression of the recombinant HDAg in bacteria was observed. The minor and major forms of HDV antigens were simultaneously expressed in bacterial strains carrying SupE mutation. A laboratory method is developed for detecting anti-HD in patients' blood. It is based on the use of minor and major forms of recombinant HDV antigen immobilized on the same membrane filter. The method can be used for creating an original highly specific test system.

[Determination of nucleotide sequences of Russian isolates of delta hepatitis virus]. / Opredelenie nukleotidnykh posledovatel'nostei rossiiskikh izoliatov virusa gepatita del'ta.

Genome RNA of hepatitis Delta virus (HDV) was isolated from the blood sera of 4 independently infected patients. The genome fragment of 901-1265 was obtained for each isolate by the RT-PCR. The resultant sequences showed that all isolates belonged to HDV genotype I. Russian isolates were shown to be closely related to an Italian one (98.1-97.5% and 97.1-95.1% identity for the nucleic acid and amino acid levels, respectively); they may represent an extra subtype within genotype I. No appreciable differences between the Russian strains were found, which fact may reflect a possible homogeneity of HDV population in North-Western Russia.

[The comparative characteristics of test systems for the diagnosis of viral hepatitis D]. / Sravnitel'naia kharakteristika test-sistem dlia diagnostiki virusnogo gepatita D.

Three Russian enzyme immunoassay kits for the detection of antibodies to hepatitis D virus (delta virus) in the blood serum were compared. Labsystems test kit was the control. Two of the examined kits were found sufficiently sensitive and specific, comparable with those of the imported agent.