Ilya M. Kirillov

The need for new effective compounds that can serve as prototype drugs for the treatment of viral infections and various types of cancer has not diminished over the past decades. This is due to the emergence of new pathogens and the development of resistance to existing drugs. Nucleoside analogues are one of the most common classes of drugs that have long served as the basis for antiviral and anticancer therapies. The analogues' similarity to natural nucleosides, which are involved in many biological processes, allows them to inhibit key enzymes in the development of pathogenic processes. The antiviral properties of synthetic nucleosides and their analogues are of great interest in connection with the primary or re-emerging viruses with epidemic and/or pandemic potential, such as Ebola, Zika, Middle East respiratory syndrome (MERS-CoV), severe acute respiratory syndrome viruses, coronaviruses 1 and 2 (SARS and SARS-CoV-2), or new strains of influenza. The aim of our work was to create new uracil derivatives—acyclic reverse fleximers as potential antiviral and antitumor agents. The substances were obtained by the Suzuki–Miyaura reaction and characterized using modern physicochemical methods. Antiviral activity against influenza A/California/7/2009 and SARS-CoV-2 was tested, and cytotoxicity was assessed on leukemia and neuroblastoma cell cultures.

Introduction. One of the more promising developments in preventing the spread of infections, including COVID-19, is the production of vaccines based on virus-like particles (VLP). Currently, in the National Research Center for Epidemiology and Microbiology named after N.F. Gamaleya of the Ministry of Health of the Russia has developed a VLP-based vaccine against COVID-19. The aim of this study is to evaluate the tolerability, safety and immunogenicity of a new vaccine for the prevention of COVID–19 based on VLP compared with placebo for 21 days after two intramuscular injections in phase I clinical trials. Materials and methods. A double-blind, placebo-controlled study of the tolerability, safety and immunogenicity of a vaccine for the prevention of COVID-19 based on VLP was conducted with a dose of the drug containing 40 and 80 micrograms of antigen, the placebo being 0.9% NaCl. The presence or absence of adverse events (AEs) after vaccination was noted in 180 volunteers aged 18 to 55 years; clinical and biochemical blood parameters, the intensity of humoral and cellular immunity before and after vaccination were assessed using enzyme immunoassay, neutralization reactions, lymphocyte blast transformation reactions and flow cytometry. Results. An analysis of the tolerability and safety of the new COVID-19 VLP-vaccine showed that most adverse events were registered within the first 10 days after vaccination, mainly after the first vaccination. In the period from 11 to 21 days after vaccination, AEs were observed in isolated cases. No deaths, serious or other AEs have been reported. The administration of the studied vaccine to the volunteers had no negative effect on the basic vital signs. A comparative analysis of immunogenicity indicators in volunteers showed that the administration of a vaccine with both an antigen content of 40 µg and an antigen content of 80 µg leads to a pronounced and significant increase in the level of specific immunoglobulins, virus neutralizing antibodies and activation of a cell-mediated immune response. As part of the phase I clinical trials, a dose of 80 µg was selected as optimal. Conclusion. It has been shown that a new vaccine for the prevention of COVID-19 based on VLP with an antigen content of 40 and 80 µg when administered intramuscularly to volunteers does not cause serious adverse events and induces a tense humoral and cellular immune response.

Introduction. The surveillance of influenza viruses in ARVI structure and study of their properties in epidemic season 2019–2020 in Russian Federation are actual for investigations due to tasks of Global Influenza Strategy initiated by WHO in 2019.Material and methods. The data of epidemiological surveillance on influenza- and ARVI-associated morbidity and hospitalization in different age groups of population were analyzed; virological, genetic and statistical methods were used.Results. Preschool children were involved in epidemic the most. Meanwhile, the highest rate of hospitalization was observed in patients of 18–40 years old. Influenza A(H1N1)pdm09 virus dominated in etiology of ARVI in hospitalized patients and pneumonia. The role of respiratory viruses in severe cases of pneumonia and bronchoalveolar syndrome in children was shown. The differences in spectrum of circulating viruses caused ARVI in different regions of Russia were found. Influenza A(H1N1)pdm09 and B/Victoria-like viruses were the main etiological agents that caused of epidemic; its activity among all ARVI was 7.3 and 8.0%, respectively. The differences in antigenic properties of influenza A(H3N2) and B epidemic strains compared to vaccine viruses were found. The populations of epidemic strains were presented by following dominant genetic groups: 6B1.A5/183P for A(H1N1)pdm09, 3С.2а1b+137F for A(H3N2) and V1A.3 line B/Victoria-like for B viruses. The good profile of epidemic strains susceptibility to anti-neuraminidase inhibitors has been saved. The most of the studied influenza strains had the receptor specificity characteristic of human influenza viruses.Conclusions. Obtained results identified the peculiarities of viruses caused the influenza and ARVI in epidemic season 2019–2020 in different regions of Russia. These results suggested the important role of influenza A(H1N1) pdm09 in severe cases and pneumonia in adults 18–40 years old. The continuing drift in influenza viruses was found, which, apparently, could not but affect the efficacy of vaccine prophylaxis and was also considered in the recommendations of WHO experts on the composition of influenza vaccines for the countries of the Northern Hemisphere in the 2020–2021 season.

Введение. Возникший в 2009 г. реассортант вируса гриппа свиней A(H1N1)pdm09 преодолел видовой барьер и стал причиной пандемии 2009-2010 гг. Одним из ключевых моментов, необходимых для преодоления вирусом гриппа видового барьера и адаптации его к человеку, является специфичность его связывания с рецепторами эпителия дыхательных путей человека. Цели и задачи. Изучение динамики рецепторной специфичности (РС) первой субъединицы гемагглютинина (НА1) штаммов вируса гриппа А(H1N1)pdm09, изолированных в 2009-2016 гг. на территории РФ, и анализ возможного влияния этих изменений на показатели заболеваемости населения РФ пандемическим гриппом в отдельные эпидемические сезоны. Материал и методы. Использованы стандартные методы сбора клинических материалов, изоляции вирусов гриппа, их типирования и секвенирования генома. Для изучения РС вируса гриппа А(H1N1)pdm09 применяли метод твердофазного сиалозидферментного анализа. Результаты. Показано, что изменение параметра W3/6, характеризующего степень превышения a2-3 рецепторной специфичности (a2-3-РС) вируса гриппа A(H1N1)pdm09 над a2-6-РС, совпадает с изменением показателей заболеваемости населения РФ пандемическим гриппом в отдельные эпидемические сезоны. Наблюдается тенденция к повышению сродства вируса А(H1N1)pdm09 к α2-3-сиалогликополимерам (СГП) - аналогам сиалил-гликановых рецепторов эпителия респираторного тракта человека, и снижению к α2-6-СГП, причём наибольшее сродство вирус проявляет к сульфатированным сиалогликополимерам. Обсуждение. Скрининг РС штаммов вируса гриппа А(H1N1)pdm09, изолированных на территории РФ в 2009-2016 гг., выявил снижение сродства вирусов к a2-6-сиалозидам, особенно к 6’SL-СГП, что, вероятно, связано с наличием аминокислотных замен в 222-й и 223-й позициях РСС НА1 вирусов. Проведённые ранее исследования показали, что наличие таких замен коррелирует с возрастанием вирулентности вируса гриппа А(H1N1)pdm09 [16, 23]. Вероятно, произошла эволюция пандемического вируса в направлении селекции более вирулентных пневмотропных вариантов. Заключение. Мониторинг РС пандемического вируса гриппа позволяет выявлять штаммы с измененной РС к эпителию респираторного тракта человека и повышенной способностью к передаче от человека к человеку. Изменение в 2009-2016 гг. параметра W3/6, характеризующего степень превышения a2-3-РС вируса гриппа A(H1N1)pdm09 над a2-6-РС, совпадает с изменением показателей заболеваемости населения РФ пандемическим гриппом в отдельные эпидемические сезоны.

Twenty years ago in the South Chinese province of Guangdong the epizooty of highly pathogenic avian influenza (HPAI) H5N1 virus, which has laid the foundation of the largest epizooty in the contemporary history, has flashed. Hemagglutinin of prototype A/goose/Guangdong/1/1996 (H5N1) changing many times and generating new genetic subgroups participated in various reassortations; it still exists today. The present review is devoted to the retrospective analysis of HPAI/H5N1evolution for the last twenty years in the territory of Eurasia, Africa and America. The basis for the discussion is ecological model according to which new genetic variants are formed in the migration pathways with close contacts between different bird populations and in the overwintering areas where the maximum values of the immune layer occur; amplification of virus variants occurs in nesting areas among juvenile populations. The updated system of designations of genetic groups introduced by WHO/OIE/FAO H5 Evolution Working Group in 2015 is used.

The peculiarities of the influenza viruses circulation in 2012-2013 are discussed. The results were obtained in 10 cities of Russia, where basic laboratories of the Influenza Ecology and Epidemics Center of on the basis of Ivanovsky Institute of Virology, Ministry of Health of the Russian Federation, are situated. The increasing rate of the ARD morbidity caused by influenza viruses was observed in January-March 2013. The highest indices of the morbidity were detected during 6-7 weeks with the following decreasing rate till threshold levels to week 14. The influenza A (H1N1) pdm09, A (H3N2), and B viruses were the cause of the epidemic, but their activity differed over areas of Russia. The results of study of the antigenic and genetic properties of the influenza strains demonstrated closed relatives with respect to vaccine strains. In addition, some heterogeneity of the circulating strains and their drift variants were found as well. All tested strains were sensitive to oseltamivir (excluding one A (H1N1) pdm09 strain), zanamivir, arbidol, and remained resistant to rimantadine. The ratio of the ARD viruses was comparable with the last epidemic seasons.

For the first time in vivo, the model of the viral pneumonia in mice was used to study the antiviral activity against influenza A virus (H1N1) pdm09 synthetic derivatives of adamantane series including the amino acid residues and lipoid acid. It was found that the adamantane derivatives with histidine, serine, and lipoid acid could inhibit the rimantadine-resistant strain of the influenza A (H1N1) pdm09. As a result, the lifespan of the mice infected with the virus has increased by 1.6 times with respect to viral control. Thus, the possibility of restoration of antiviral properties of rimantadine both in vitro and in vivo by introducing into its molecular structure new functionally active groups was tested.

The receptor specificity (RS) of pandemic influenza A(H1N1) pdm09 virus strains deposited into the State Collection of Viruses of the Russian Federation, D. I. Ivanovsky Research Institute of Virology, Ministry of Health and Social Development of Russia, in the 2009-2010 and 2010-2011 epidemic seasons to a panel of 9 sialoglycopolymers (SGP). The strains were divided into 3 groups according to the W(3/6) index proposed by the authors, which was equal to the amount of reactivities to unbranched alpha2-3-SGP to that of reactivities to unbranched alphal-6-SGP: W(3/6) < or = 1.0; 1.0 < W(3/6) < or = 1.5. The W(3/6) < or = 1.5 group showed a predominance of a2-3-RS, attended by the high incidence of fatal primary viral pneumonias (FPVP) (60.0%) and amino acid replacements in the HA1 receptor-binding site (RBS) (80.0%): D222{G, N} and Q223R. The 1.0 < W(3/6) < or = 1.5 group was characterized by mixed alpha2-3/alpha2-6-RS with the incidence of FPVP (29.7%) and amino acid replacements in the HA1 RBS (40.5%) (D222{G, N, V} and Q223), respectively. In the W(3/6) < or = 1.0 group, alpha2-6-RS was prevalent, FPVPs were absent and amino acid replacements in HA1 RBS (D222{G, E}) were seen only in 6.0% of cases. The number of strains with increased specificity to alpha2-3-sialosides increased in the 2010-2011 epidemic season as compared to the previous season. With their further spread among the population, there may be a rise in cases of severe primary viral pneumonias with possible fatal outcomes, which can be, however, accompanied by a decrease in the capacity of mutants to air-dropwise transmission.

An influenza virus A/gull/Moscow/3100/2006 (H6N2) was isolated from gull’ faeces within the precincts of Moscow in autumn 2006. Nucleotide sequence of 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, which have been circulating among different birds in Europe since 1999 and in South-East Asia (NA gene) for last years. Some of these viruses probably were introduced by migratory birds from South-East Asia earlier. The strain A/gull/Moscow/3100/2006 is nonpathogenic for chicken embryos and mice and induces specific antibody production in mice. Similar to all avian influenza viruses A/gull/Moscow/3100/2006 binds to Neu5Acα2–3Gal receptors but reveals higher affinity for fucosylated sialosugars (SLex) in contrast to the duck viruses, as was shown in receptor specificity assay and clarified due to modeling the accommodation of SLex into receptor binding site of duck and gull influenza virus hemagglutinin.