Assessment of rat polyclonal antisera's suitability in hemagglutination inhibition assay for influenza surveillance and antigenic mapping.

This paper presents comparative hemagglutination inhibition (HI) assay data obtained using ferret or rat antisera to analyze influenza viruses. The results indicate that rat antisera can be successfully applied both for identification and for antigenic analysis of human influenza A and B viruses. Data gained with rat antisera were comparable to those obtained with ferret antisera. In-depth statistical analysis, based on Confusion Matrix analysis and Receiver Operating Characteristic (ROC) analysis, confirmed good coincidence between ferret antisera-based and rat antisera-based results. Two-dimensional antigenic mapping, based on HI assays using rat and ferret antisera, supported these findings. Both antisera types yielded identical antigenic attributions for the viruses analyzed, and both permitted visualization of contemporary human influenza virus evolutionary trends.

PROBLEMS OF ISOLATION, IDENTIFICATION AND ANTIGENIC CHARACTERIZATION OF RECENT HUMAN A(H3N2) INFLUENZA VIRUSES.

Human A (H3N2) influenza viruses are distinguished by a high rate of evolution and regularly cause epidemics around the world. Their ability to adapt and to escape from the host's immune response and to change their receptor specificity is very high. Over the past 20 years, these viruses have lost the ability to agglutinate red blood cells of chickens and turkeys and have practically ceased to propagate in chicken embryos - the main source of influenza vaccines. Isolation of viruses in the MDCK cell culture led to the selection of strains that lose one of the potential glycosylation sites. Many of the A (H3N2) strains have acquired mutations in neuraminidase, which distort the results of antigenic analysis in the hemagglutination inhibition test - the cornerstone method for the analysis of the match between viral isolates circulating in human population to strains selected for the influenza vaccines. In this regard, the characteristics of the antigenic properties of influenza A (H3N2) viruses by traditional methods become poorly informative, and the selection of vaccine strains of this subtype is erroneous, which is reflected in the discrepancy between vaccine and circulating A (H3N2) viruses in recent years (2013-2014, 2014 -2015, 2015-2016). The search, development and implementation of new algorithms for the isolation and antigen analysis of influenza A (H3N2) viruses are extremely urgent.

Synthesis and antiviral activity of novel glycyrrhizic acid conjugates with D-amino acid esters.

Glycyrrhizic acid (GA) conjugates with methyl and ethyl esters of D-amino acids (D-Trp, D-Phe, D-Tyr, D-Val, D-Leu) have been synthesized by the activated esters method using mixtures of N-hydroxybenzotriazole or N-hydroxysuccinimide with N,N'-dicyclohexylcarbodiimide. GA conjugate with D-Trp ethyl ester exhibited antiviral activity against influenza viruses A/H3N2, A/H1N1/pdm09, A/H5N1, B (SI > 10-29), and HRSV (SI > 25). GA conjugate with D-Trp methyl ester inhibited influenza virus A/H1N1/pdm09 (SI > 30).

[Clinical and laboratory presentation of the influenza A (H1N1pdm 2009) in children and adults during the period of 2009-2013 in St. Petersburg].

Comparative analysis of the clinical laboratory data from 419 children and 468 adults hospitalized during the pandemic of A (H1N1pdm 2009) and pre- and post-pandemic periods (2010-2013) showed that the clinical presentation of the pandemic influenza in patients of all ages is generally typical for influenza, and its character is determined by the degree of involvement of lungs in the process. Besides, the incidence of pneumonia in adults is statistically significantly higher than in children. During all compared periods hyperthermia (≥ 39 degrees C), hemorrhagic and dyspeptic syndrome were observed. Some differences in the main clinical manifestations of pneumonia in recovered patients and patients who died of the severe pandemic influenza were observed. The regularities of the cytokine reactions depending on the intensity of intoxication and occurrence of complications were determined in patients of all ages. Medical efficacy of inclusion of antiviral chemotherapeutic agents into complex influenza treatment was proved.

[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.

[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.

[Pandemic influenza 2009 in Russia. Characteristics of the isolation and biological properties of viruses].

Research Institute of Influenza, Ministry of Health and Social Development of Russia, Saint Petersburg The characteristics of the isolation of pandemic influenza A(H1N1)v viruses were studied on chick embryos (CE) and MDCK cell culture. The materials (nasal swabs and autopsies) were collected in different regions Russia in the period from 20 July to 30 December 2009. The paper gives the data of the antigenic analysis of isolates, their capacity to multiply in different species-specific and tissue cell cultures. The viruses isolated on CE were shown to have higher hemagglutination titers and to be more stable. Isolation from the autopsies was effective only on CE. All the test cell lines other than MDCK were insensitive to the isolated pandemic influenza strains. The antigenic analysis showed no significant antigenic drift of the viruses isolated during the first wave of the pandemic in the Russian Federation.

[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.

[Etiological characteristics of the influenza epidemics of 2006-2009 in the Russian Federation (according to the data of the Research Institute of Influenza, North-Western Branch, Russian Academy of Medical Sciences)].

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.

Synthesis and biological activity of water-soluble polymer complexes of arbidol.

We have synthesized water-soluble complexes between the antiviral drug arbidol and polymer compounds with molecular masses of 19-31 kDa representing copolymers of acrylamide (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AAMPS). The complexes are less toxic than arbidol and retain the high level of antiviral activity of this drug. The content of arbidol in the obtained complexes is within 26.4-32.1 mass%. The antiviral activity of the synthesized polymeric complexes against all studied viruses, including human epidemic influenza virus A (H3N2), bird highly pathogenic influenza virus A (H5N1), herpes type 1 virus (HSV-1), and adenovirus type III (AV-III) is comparable to the antiviral effect of nonmodified arbidol. The in vitro toxicity of the obtained complexes is about one order of magnitude lower than that of nonmodified arbidol; the pharmacological index, four times that of the initial low-molecular-weight drug. The synthesized water-soluble polymer complexes of arbidol can be useful in pharmacology since they can serve as the basis for new effective and safe parent antiviral substances and related formulations.

[Antiviral action of some antioxidants/antihypoxants and their combinations with remantadine against human influenza A(H3N2) virus studied in in vitro models].

The possible antiviral activity of preparations with antioxidant and/or antihypoxant properties was studied on two in vitro models of influenza infection: (i) in cultures of chorio-allantoic membranes of chicken embryos and (ii) in MDCK cells. Preparations under study were hypoxene, reduced glutathione, dihydroquercetin, trolox, coenzyme Q10, and the enzymatic preparation of superoxide-dismutase (recsod). Preparations possessing combined antioxidant/antihypoxic and detoxicating properties (reduced glutathione and hypoxene) produced a significant antiviral effect and enhanced the antiviral effect of rimantadine. The antiviral effect of these preparations was manifested by a decrease in the production of viral particles and, to a more pronounced degree, by the inhibition of cytopathogenic action of virus on cultured cells, which was revealed in the tests for the activity of respiratory enzymes. In contrast to the compounds containing thio or sulfo groups, the antioxidants of "direct action" (free radical scavengers) - coenzyme Q 10, trolox, quercetin and the enzymatic preparation recsod did not show any pronounced protective effect and in some cases even enhanced the production of viral particles and decreased the antiviral action of rimantadine.

Etiology of influenza viruses isolated in Russia from 1998 up to present time.

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.

[The antimetastatic effect of low doses of lonidamine]. / Antimetastaticheskii éffekt nizkikh doz lonidamina.

Antimetastatic activity of a wide range of Lonidamine doses, including low and ultralow doses, was studied. Low doses of the drug were shown to affect the frequency and intensity of metastasis formation.

[Features of interepidemic influenza A and B viruses]. / Osobennosti mezhépidemicheskikh virusov grippa A i B.

The comparison of interepidemic influenza viruses with the pathogens of resultant influenza epidemics has revealed that they belong to the same type (subtype) of influenza virus. A definite correlation has been found between the antigenic specificity of haemagglutinin of epidemic and interepidemic strains. The antigenic structure of the interepidemic viruses and the pathogens of further epidemics of influenza B viruses have been found to be completely identical. The interepidemic A(H1N1) isolates have been shown to be antigenic analogues of the causative agents of influenza A(H1N1) during the previous epidemics. Despite the time and place of their isolation, as well as the etiology of the previous and subsequent epidemics, the interepidemic influenza A(H3N2) viruses have been ascertained to be similar to the reference A/Bangkok/1/79.

[Genetic predisposition to latent influenza A virus in children with blood type B(III) as a possible cause of new epidemiologic strains in the countries of South-Eastern Asia]. / Geneticheskaia predraspolozhennost detei s gruppoi krovi B(III) k latentnomu nositelstvu virusov grippa A - vozmozhnaia prichina vozniknoveniia novykh épidemicheskikh shtammov v stranakh Iugo- Vostochnoi Azii.

Regular clinical and epidemiological surveys of two groups of healthy 14-16-year-old boys were carried out for 3 years from September 1989 to May 1992 to investigate the latent circulation of influenza A viruses in the human population. Once or twice a quarter clinical materials were laboratorily studied to detect virus antigens, virus-specific NA-sequences and to determine changes in humoral immunity. The latent circulation of influenza A viruses might be identified in 10-20% of cases long before (2-4 months) the onset of epidemic development. The incidence of epidemic isolations was found to reach 33-36%, gradually decreasing from 29 to 9 or 3.5% in the postepidemic period. The long-term persistence (for 5 months) of virus antigens was reported among healthy children who had chiefly blood group B(III). The new hypothesis that the genetic predisposition of children with blood group B(III) to latent persistence of influenza A viruses may be a possible cause of the emergence of new epidemic strains in the South-East Asian countries has been forwarded.