Problems of Virology

Animal rotaviruses (RV) play a significant role in the formation of new variants of epidemiologically significant human group A rotavirus (RVA) strains.A reassortant variant of genotype G3P[8] which has been shown to originate from RV in horses and cattle currently dominates on the territory of the Russian Federation. In addition, reassortant RV variants of genotypes G3P[3], G3P[9], G6P[9], similar to RV of cats and dogs, have been sporadically identified in the world for a long time. Given the relevance of this topic, a detailed study of the AU-1-like genetic group of RVAs, whose representatives are closely related to animal RVs, particularly those found in cats and dogs, is of scientific and practical interest.

The aim of this review is to analyze published scientific data on human, feline and canine RV that belong to the AU-1-like genetic group and have been studied based on their complete genotypes.

Introduction. The Vif protein counteracts cellular deaminases, APOBEC3, which prevent viral replication. Vif is used for development of therapeutic agents. Natural polymorphisms in Vif can affect its functionality and may be associated with accelerated progression of HIV-infection to the AIDS. The study of Vif features in HIV-1 variants circulating in Russia has not been conducted previously.

The aim of the study: to study the genetic diversity of Vif in the HIV-1 variants that circulated in the Moscow region in 2019–2020.

Materials and methods. 234 whole blood samples obtained from HIV-infected patients without experience of therapy were analyzed. The study design included the following stages: extraction of proviral DNA, amplification of the vif gene, sequencing, identification of genetic variants, followed by a study of consensus sequences of the most common genetic variants of HIV-1, analysis of the conservation and genetic diversity of Vif-A6 (Vif protein of HIV-1 sub-subtype A6 variants) in patients with different stages of the disease, and assessment of genetic diversity of Vif-A6 in the Moscow region.

Results. A high degree of genetic diversity of vif gene was revealed. Consensus sequences of Vif in B and CRF63_02A6 variants were obtained for the first time. Characteristic substitutions in the consensus sequences were determined for the most common HIV-1 variants.

Conclusion. The limitation of this study is the small sample of B and CRF63_02A6. The results obtained may be of interest and may be taken into account in the development of therapeutic agents based on the Vif protein, as well as in the study of the pathogenicity of HIV-1 sub-subtype A6.

Introduction. Tick cell lines are widely used to study the biology of ticks and tick-borne pathogens, especially viruses. Most of the cell cultures currently available have been obtained from tick embryonic cells and can be infected with viruses. The HAE/CTVM8 cell line was obtained from Hyalomma anatolicum ticks and is often used for isolation of novel viruses.

The aim of the work is to study the HAE/CTVM8 cell line using high-throughput sequencing in order to search for viruses in it.

Materials and methods. The HAE/CTVM8 cell culture fluid was ultracentrifuged. The resulting pellet was used for high-throughput sequencing after RNA extraction, reverse transcription reaction, and synthesis of the second strand. The resulting reads were filtered by length and quality in the Trimmomatic program, after which the contigs were assembled using the SPAdes program and analyzed for the presence of viral sequences. The final assembly of the virus genome was carried out in the Ugene program. Sequence alignment was performed by the MAFFT program. The phylogenetic trees were constructed using the IQ-TREE program.

Results. We have identified the persistence of one virus, Liman tick virus (LMTV), in HAE/CTVM8 cell culture. Phylogenetically LMTV belongs to the Chuviridae – novel family, that consists of viruses detected by high-throughput sequencing, the virological characteristics of which are currently unknown.

Conclusion. The obtained information is of significant importance when utilizing HAE/CTVM8 cell culture in scientific research and during the process of isolating new viruses. Our study shows that this cell line with persistent LMTV is a ready-to-use system for studying Chuviridae reproduction

Introduction. Human metapneumovirus (hMPV) holds significant epidemiological importance, being a dominant cause of lower respiratory tract infections in children under two years of age and individuals over 65. Multiple infections with hMPV throughout a person’s life are possible due to the antigenic and genetic variability of the virus. However, the genetic variability of hMPV circulating in Russia remains unexplored.

Aim of the study. The aim of this study was to test a protocol for whole-genome sequencing of hMPV to assess the genetic diversity of metapneumoviruses circulating in certain regions of Russia.

Materials and methods. Nasopharyngeal swabs were collected from patients of different ages with acute respiratory viral infections (ARVI) tested positive for hMPV using polymerase chain reaction (PCR). From some of the samples, viral isolates were obtained in cell culture. Whole-genome sequencing was performed on both swabs and isolates using the MiSeq Illumina platform, followed by phylogenetic analysis.

Results. For the first time in Russia, whole-genome sequencing of 44 hMPV strains circulating from 2017 to 2024 was conducted. Their genetic group affiliation was described, with the A2b2 clade shown to dominate. It was confirmed that the greatest variability among genes encoding viral surface proteins was observed in the G gene, while changes in the F gene were minimal during the studied period.

Conclusion. The study provides insights into the genetic diversity of hMPV strains circulating in various regions of the Russian Federation. Understanding the genetic variability of hMPV is crucial for comprehending viral evolution, transmission dynamics, and mechanisms of immune evasion, which influence the development of vaccines and antiviral drugs.

Introduction. Enterovirus infection, widespread in the world and in Russia, is characterized by a variety of clinical forms, one of which is serous meningitis. The most common cause of enterovirus meningitis in children is echovirus 30 (E30). Previously, we obtained a chimeric protein consisting of the S domain of norovirus VP1 protein(S_N), fused into one molecule with VP1 protein of E30 (S_N-VP1_E30), which in the future can be used to develop a vaccine for the prevention of enterovirus meningitis caused by the E30 virus.

The aim of this work was to study the immunological properties of the S_N-VP1_E30 protein.

Materials and methods. Balb/c mice and a guinea pig were immunized with the S_N-VP1_E30 protein. The production of IgG and IgM antibodies was studied by ELISA. The interaction of antibodies against S_N-VP1_E30 with virions of enteroviruses E30 of different genotypes was studied by electron microscopy. The reaction of neutralization of E30 by antibodies was carried out in vitro in RD cells.

Results. In mice immunized with S_N-VP1_E30 without adjuvant, the average titers of total antibodies against E30 VP1 protein were 1 : 19,000. The use of adjuvant increased the average titer of antibodies by 3 times. The level of IgM antibodies was significantly lower and amounted to, on average, 1 : 1500. Using immunoelectron microscopy, it was shown that guinea pig antibodies against chimeric S_N-VP1_E30 are able to bind virions of E30 genotypes h and eC2. Mouse and guinea pig antibodies were able to neutralize E30 in RD cell line. Neutralizing antibody titers in mice varied from 20 to 40, and were 40 in guinea pigs.

Conclusion. The immunogenicity of S_N-VP1_E30 in two animal species and the ability of antibodies to bind and neutralize enterovirus E30 allows us to propose it as an antigen in a vaccine for the prevention of diseases caused by E30.