Isolation of clade 2.3.4.4b A(H5N8), a highly pathogenic avian influenza virus, from a worker during an outbreak on a poultry farm, Russia, December 2020.

This study presents the isolation of influenza A(H5N8) virus clade 2.3.4.4b from a poultry worker during an outbreak of highly pathogenic avian influenza A(H5N8) among chickens at a poultry farm in Astrakhan, Russia in December 2020. Nasopharyngeal swabs collected from seven poultry workers were positive for influenza A(H5N8), as confirmed by RT-PCR and sequencing. The influenza A(H5N8) virus was isolated from one of the human specimens and characterised. Sporadic human influenza A(H5)2.3.4.4. infections represent a possible concern for public health.

Deletion of BST2 Cytoplasmic and Transmembrane N-Terminal Domains Results in SARS-CoV, SARS-CoV-2, and Influenza Virus Production Suppression in a Vero Cell Line.

SARS-CoV-2, which emerged in Wuhan (China), has become a great worldwide problem in 2020 and has led to more than 1,000,000 deaths worldwide. Many laboratories are searching for ways to fight this pandemic. We studied the action of the cellular antiviral protein tetherin, which is encoded by the BST2 gene. We deleted the transmembrane domain-encoding part of the gene in the Vero cell line. The transmembrane domain is a target for virus-antagonizing proteins. We showed a decrease in SARS-CoV-2 in cells with deleted transmembrane BST2 domains compared to the initial Vero cell line. Similar results were obtained for SARS-CoV and avian influenza virus. This finding may help the development of antiviral therapies competitively targeting the transmembrane domain of tetherin with viral-antagonizing proteins.

Humoral immunity to influenza in an at-risk population and severe influenza cases in Russia in 2016-2017.

This work aimed to analyze the herd immunity to influenza among a Russian population living in regions with an increased risk of emergence of viruses with pandemic potential, and to isolate and investigate virus strains from severe influenza cases, including fatal cases, during the 2016-2017 epidemic season. In November 2016 - March 2017 highly pathogenic influenza outbreaks were registered in Russia among wild birds and poultry. No cases of human infection were registered. Analysis of 760 sera from people who had contact with infected or perished birds revealed the presence of antibodies to A(H5N1) virus of clade 2.3.2.1c and A(H5N8) virus of clade 2.3.4.4. The 2016-2017 influenza epidemic season in Russia began in weeks 46-47 of 2016 with predominant circulation of influenza A(H3N2) viruses. Strains isolated from severe influenza cases mainly belonged to 3C.2a.2 and 3C.2a.3 genetic groups. Up to the 8th week of 2017 severe influenza cases were often caused by influenza B viruses which belonged to 1A genetic group with antigenic properties similar to B/Brisbane/60/2008. All influenza A and B virus strains isolated in the 2016-2017 epidemic season were sensitive to oseltamivir and zanamivir.

Survival of aerosolized coronavirus in the ambient air.

An inactivation of airborne pathogenic Middle East Respiratory Syndrome (MERS-CoV) virus was investigated under controlled laboratory conditions. Two sets of climatic conditions were used in the experiments; (1) representing common office environment (25 °C and 79% RH) and (2) climatic conditions of the Middle Eastern region where the virus was originated from (38 °C and 24% RH). At the lower temperature, the virus demonstrated high robustness and strong capability to survive with about 63.5% of microorganisms remaining infectious 60 min after aerosolisation. Fortunately, virus decay was much stronger for hot and dry air scenario with only 4.7% survival over 60 min procedure.

Successful post-exposure prophylaxis of Ebola infected non-human primates using Ebola glycoprotein-specific equine IgG.

Herein we describe production of purified equine IgG obtained from horses immunized with plasmid DNA followed by boosting with Kunjin replicon virus-like particles both encoding a modified Ebola glycoprotein. Administration of the equine IgG over 5 days to cynomolgus macaques infected 24 hours previously with a lethal dose of Ebola virus suppressed viral loads by more than 5 logs and protected animals from mortality. Animals generated their own Ebola glycoprotein-specific IgG responses 9-15 days after infection, with circulating virus undetectable by day 15-17. Such equine IgG may find utility as a post-exposure prophylactic for Ebola infection and provides a low cost, scalable alternative to monoclonal antibodies, with extensive human safety data and WHO-standardized international manufacturing capability available in both high and low income countries.

A Kunjin Replicon Virus-like Particle Vaccine Provides Protection Against Ebola Virus Infection in Nonhuman Primates.

The current unprecedented outbreak of Ebola virus (EBOV) disease in West Africa has demonstrated the urgent need for a vaccine. Here, we describe the evaluation of an EBOV vaccine candidate based on Kunjin replicon virus-like particles (KUN VLPs) encoding EBOV glycoprotein with a D637L mutation (GP/D637L) in nonhuman primates. Four African green monkeys (Cercopithecus aethiops) were injected subcutaneously with a dose of 10(9) KUN VLPs per animal twice with an interval of 4 weeks, and animals were challenged 3 weeks later intramuscularly with 600 plaque-forming units of Zaire EBOV. Three animals were completely protected against EBOV challenge, while one vaccinated animal and the control animal died from infection. We suggest that KUN VLPs encoding GP/D637L represent a viable EBOV vaccine candidate.

Polyepitope protein incorporated the HIV-1 mimotope recognized by monoclonal antibody 2G12.

A major goal in HIV-1 vaccine research is to develop an immunogen that can elicit broadly neutralizing antibodies that efficiently neutralize a wide range of the HIV-1 subtypes. Using biopanning procedure we have selected linear peptide VGAFGSFYRLSVLQS mimicking the structure of discontinuous binding sites of broadly neutralizing antibodies 2G12 from phage peptide library. As a protein carrier, we used the earlier designed artificial polyepitope immunogen named TBI (T- and B-cell immunogen), which comprises B-cell and T-helper epitopes from the HIV-1 Env and Gag proteins. On the base of selected peptide mimotope VGAFGSFYRLSVLQS the artificial protein TBI-2g12 was constructed and its immunogenic properties was investigated. It was shown that the TBI-2g12 as well as the original TBI induces antibodies that recognize HIV-1 proteins and TBI protein using ELISA and immunoblotting. However only anti-TBI-2g12 serum recognized the synthetic peptide mimotope VGAFGSFYRLSVLQS, whereas the antibodies against original TBI don't recognize it. The neutralization assay demonstrated that serum antibodies of the mice immunized with TBI-2g12 possess virus neutralizing activity. The addition of selected peptide leads to inhibition neutralizing activity of anti- TBI-2g12 serum. We conclude from these results that immunogen TBI-2g12 containing the selected peptide VGAFGSFYRLSVLQS elicits HIV-1 neutralizing antibodies during immunization. Our data suggest that this immunogen may be useful in designing effective HIV-vaccine candidates.