Emergence and spread of SARS-CoV-2 lineage B.1.620 with variant of concern-like mutations and deletions.

Distinct SARS-CoV-2 lineages, discovered through various genomic surveillance initiatives, have emerged during the pandemic following unprecedented reductions in worldwide human mobility. We here describe a SARS-CoV-2 lineage - designated B.1.620 - discovered in Lithuania and carrying many mutations and deletions in the spike protein shared with widespread variants of concern (VOCs), including E484K, S477N and deletions HV69Δ, Y144Δ, and LLA241/243Δ. As well as documenting the suite of mutations this lineage carries, we also describe its potential to be resistant to neutralising antibodies, accompanying travel histories for a subset of European cases, evidence of local B.1.620 transmission in Europe with a focus on Lithuania, and significance of its prevalence in Central Africa owing to recent genome sequencing efforts there. We make a case for its likely Central African origin using advanced phylogeographic inference methodologies incorporating recorded travel histories of infected travellers

Optimization of polyomavirus VP1 protein biosynthesis in S. cerevisiae cells and application of recombinant virus-like particles for serology.

In this study, a targeted genetic approach to optimize PyV VP1 proteins synthesis in S. cerevisiae cells was performed. The requirement for molecular chaperones during biosynthesis of PyV capsid protein VP1 was evaluated, the reasons of yeast flocculation caused by expression of recombinant VP1 protein derived from some PyV was investigated and the impact of NLS in WU VP1 N-termini for VLPs formation was analysed. The yeast expression system was successfully utilized for high-throughput production of recombinant VP1-derived VLPs from 11 newly identified human PyVs for the first time. Human PyV VP1-derived VLPs were generated from the second of two potential translation initiation sites in the VP1-encoding open reading frame. Recombinant VLPs produced in yeast originated from different HPyVs demonstrated distinct hemagglutinating activities (in hemagglutinating assay) and may be useful in virus diagnostics. All purified HPyV VP1 VLPs were used to develop indirect enzyme immunoassay for detection of HPyVs specific antibodies in human sera samples. Human PyVs are part of the normal microbial flora and the infection of these viruses in their host is thought to be asymptomatic but, when host immunity is compromised the infection can cause acute systemic disease or tumor induction

Poliomos virusų VP1 baltymų biosintezės ypatybių S. cerevisiae ląstelėse tyrimas bei panaudojimas serologiniams tyrimams” antotacija

In this study, a targeted genetic approach to optimize PyV VP1 proteins synthesis in S. cerevisiae cells was performed. The requirement for molecular chaperones during biosynthesis of PyV capsid protein VP1 was evaluated, the reasons of yeast flocculation caused by expression of recombinant VP1 protein derived from some PyV was investigated and the impact of NLS in WU VP1 N-termini for VLPs formation was analysed. The yeast expression system was successfully utilized for high-throughput production of recombinant VP1-derived VLPs from 11 newly identified human PyVs for the first time. Human PyV VP1-derived VLPs were generated from the second of two potential translation initiation sites in the VP1-encoding open reading frame. Recombinant VLPs produced in yeast originated from different HPyVs demonstrated distinct hemagglutinating activities (in hemagglutinating assay) and may be useful in virus diagnostics. All purified HPyV VP1 VLPs were used to develop indirect enzyme immunoassay for detection of HPyVs specific antibodies in human sera samples. Human PyVs are part of the normal microbial flora and the infection of these viruses in their host is thought to be asymptomatic but, when host immunity is compromised the infection can cause acute systemic disease or tumor induction

Practical aspects of compiling the English-Lithuanian dictionary of aircraft maintenance terms

Technical dictionaries play a very important role in modern world of technological changes and international cooperation. In Lithuania, with the Lithuanian Air Force procuring aircraft equipped with the newest technology, there is an increasing need for technical personnel to correctly and precisely understand manuals and documentation accompanying the procured aircraft. Since there had been no English-Lithuanian dictionary of this kind in Lithuania, in the course of teaching technical English to aircraft maintenance personnel, the authors of the article compiled an English-Lithuanian dictionary of aircraft maintenance terms intended not only for the students of the course, but also for all specialists working in this field. The authors share their experience in the compilation of the dictionary. The article indicates the reasons for the emergence of the dictionary, presents the sources and criteria of word selection as well as the sources of Lithuanian equivalents. Also discussed are the problems related to illustrative examples and difficulties of providing Lithuanian equivalents

Structural properties of immune complexes formed by viral antigens and specific antibodies shape the inflammatory response of macrophages

Abstract Data on the course of viral infections revealed severe inflammation as a consequence of antiviral immune response. Despite extensive research, there are insufficient data on the role of innate immune cells in promoting inflammation mediated by immune complexes (IC) of viral antigens and their specific antibodies. Recently, we demonstrated that antigens of human polyomaviruses (PyVs) induce an inflammatory response in macrophages. Here, we investigated macrophage activation by IC. We used primary murine macrophages as a cell model, virus-like particles (VLPs) of PyV capsid protein as antigens, and a collection of murine monoclonal antibodies (mAbs) of IgG1, IgG2a, IgG2b subclasses. The inflammatory response was investigated by analysing inflammatory chemokines and activation of NLRP3 inflammasome. We observed a diverse pattern of chemokine secretion in macrophages treated with different IC compared to VLPs alone. To link IC properties with cell activation status, we characterised the IC by advanced optical and acoustic techniques. Ellipsometry provided precise real-time kinetics of mAb-antigen interactions, while quartz crystal microbalance measurements showed changes in conformation and viscoelastic properties during IC formation. These results revealed differences in mAb-antigen interaction and mAb binding parameters of the investigated IC. We found that IC-mediated cell activation depends more on IC characteristics, including mAb affinity, than on mAb affinity for the activating Fc receptor. IC formed by the highest affinity mAb showed a significant enhancement of inflammasome activation. This may explain the hyperinflammation related to viral infection and vaccination. Our findings demonstrate that IC promote the viral antigen-induced inflammatory response depending on antibody properties

Immunogenic properties and antigenic similarity of virus-like particles derived from human polyomaviruses /

Polyomaviruses (PyVs) are highly prevalent in humans and animals. PyVs cause mild illness, however, they can also elicit severe diseases. Some PyVs are potentially zoonotic, such as simian virus 40 (SV40). However, data are still lacking about their biology, infectivity, and host interaction with different PyVs. We investigated the immunogenic properties of virus-like particles (VLPs) derived from viral protein 1 (VP1) of human PyVs. We immunised mice with recombinant HPyV VP1 VLPs mimicking the structure of viruses and compared their immunogenicity and cross-reactivity of antisera using a broad spectrum of VP1 VLPs derived from the PyVs of humans and animals. We demonstrated a strong immunogenicity of studied VLPs and a high degree of antigenic similarity between VP1 VLPs of different PyVs. PyV-specific monoclonal antibodies were generated and applied for investigation of VLPs phagocytosis. This study demonstrated that HPyV VLPs are highly immunogenic and interact with phagocytes. Data on the cross-reactivity of VP1 VLP-specific antisera revealed antigenic similarities among VP1 VLPs of particular human and animal PyVs and suggested possible cross-immunity. As the VP1 capsid protein is the major viral antigen involved in virus-host interaction, an approach based on the use of recombinant VLPs is relevant for studying PyV biology regarding PyV interaction with the host immune system

Activation of NLRP3 inflammasome by virus-like particles of human polyomaviruses in macrophages

Viral antigens can activate phagocytes, inducing inflammation, but the mechanisms are barely explored. The aim of this study is to investigate how viral oligomeric proteins of different structures induce inflammatory response in macrophages. Human THP-1 cell line was used to prepare macrophages that were treated with filamentous nucleocapsid-like particles (NLPs) of paramyxoviruses and spherical virus-like particles (VLPs) of human polyomaviruses. The effects of viral proteins on cell viability, pro-inflammatory cytokines' production, and NLRP3 inflammasome activation were investigated. Filamentous NLPs did not induce inflammation while spherical VLPs mediated inflammatory response followed by NLRP3 inflammasome activation. Inhibitors of cathepsins and K+ efflux decreased IL-1β release and cell death, indicating a complex inflammasome activation process. A similar activation pattern was observed in primary human macrophages. Single-cell RNAseq analysis of THP-1 cells revealed several cell activation states different in inflammation-related genes. This study provides new insights into the interaction of viral proteins with immune cells and suggests that structural properties of oligomeric proteins may define cell activation pathways

Emergence and spread of SARS-CoV-2 lineage B.1.620 with variant of concern-like mutations and deletions

Distinct SARS-CoV-2 lineages, discovered through various genomic surveillance initiatives, have emerged during the pandemic following unprecedented reductions in worldwide human mobility. We here describe a SARS-CoV-2 lineage - designated B.1.620 - discovered in Lithuania and carrying many mutations and deletions in the spike protein shared with widespread variants of concern (VOCs), including E484K, S477N and deletions HV69Δ, Y144Δ, and LLA241/243Δ. As well as documenting the suite of mutations this lineage carries, we also describe its potential to be resistant to neutralising antibodies, accompanying travel histories for a subset of European cases, evidence of local B.1.620 transmission in Europe with a focus on Lithuania, and significance of its prevalence in Central Africa owing to recent genome sequencing efforts there. We make a case for its likely Central African origin using advanced phylogeographic inference methodologies incorporating recorded travel histories of infected travellers