Development, production and characterization of SARS-CoV-2 virus-like particles (Coronaviridae: <i>Orthocoronavirinae: Betacoronavirus: Sarbecovirus</i>)

Introduction. The COVID-19 pandemic caused by SARS-CoV-2 has created serious health problems worldwide. The most effective way to prevent the occurrence of new epidemic outbreaks is vaccination. One of the modern and effective approaches to vaccine development is the use of virus-like particles (VLPs). The aim of the study is to develop a technology for production of VLP based on recombinant SARS-CoV-2 proteins (E, M, N and S) in insect cells. Materials and methods. Synthetic genes encoding coronavirus proteins E, M, N and S were used. VLP with various surface proteins of strains similar to the Wuhan virus, Delta, Alpha and Omicron were developed and cloned into the pFastBac plasmid. The proteins were synthesized in the baculovirus expression system and assembled into VLP in the portable Trichoplusia ni cell. The presence of insertion in the baculovirus genome was determined by PCR. ELISA and immunoblotting were used to study the antigenic activity of VLP. VLP purification was performed by ultracentrifugation using 20% sucrose. Morphology was assessed using electron microscopy and dynamic light scattering. Results. VLPs consisting of recombinant SARS-CoV-2 proteins (S, M, E and N) were obtained and characterized. The specific binding of antigenic determinants in synthesized VLPs with antibodies to SARS-CoV-2 proteins has been demonstrated. The immunogenic properties of VLPs have been studied. Conclusion. The production and purification of recombinant VLPs consisting of full-length SARS-CoV-2 proteins with a universal set of surface antigens have been developed and optimized. Self-assembling particles that mimic the coronavirus virion induce a specific immune response against SARS-CoV-2

Genome Characterization of a Pathogenic Porcine Rotavirus B Strain Identified in Buryat Republic, Russia in 2015

Citation: Alekseev, K.P.; Penin, A.A.; Mukhin, A.N.; Khametova, K.M.; Grebennikova, T.V.; Yuzhakov, A.G.; Moskvina, A.S.; Musienko, M.I.; Raev, S.A.; Mishin, A.M.; Kotelnikov, A.P.; Verkhovsky, O.A.; Aliper, T.I.; Nepoklonov, E.A.; Herrera-Ibata, D.M.; Shepherd, F.K.; Marthaler, D.G. Genome Characterization of a Pathogenic Porcine Rotavirus B Strain Identified in Buryat Republic, Russia in 2015. Pathogens 2018, 7, 46.An outbreak of enteric disease of unknown etiology with 60% morbidity and 8% mortality in weaning piglets occurred in November 2015 on a farm in Buryat Republic, Russia. Metagenomic sequencing revealed the presence of rotavirus B in feces from diseased piglets while no other pathogens were identified. Clinical disease was reproduced in experimentally infected piglets, yielding the 11 RVB gene segments for strain Buryat15, with an RVB genotype constellation of G12-P[4]-I13-R4-C4-M4-A8-N10-T4-E4-H7. This genotype constellation has also been identified in the United States. While the Buryat15 VP7 protein lacked unique amino acid differences in the predicted neutralizing epitopes compared to the previously published swine RVB G12 strains, this report of RVB in Russian swine increases our epidemiological knowledge on the global prevalence and genetic diversity of RVB

CHANGES IN URINE MICROFLORA IN CHILDREN WITH COMMUNITY-ACQUIRED URINARY TRACT INFECTION ADMITTED TO HOSPITAL BETWEEN 1990 AND 2015: A RETROSPECTIVE FULL-DESIGN STUDY OF CASE SERIES

Background. It is necessary to study the microbial spectrum of urine in order to determine the features of the urinary tract infection (UTI) course and to make the right choice of a therapeutic approach. Objective. Our aim was to study the structure of urine microflora in children with community-acquired UTI and its change in the period from 1990 to 2015.Methods. We conducted a continuous analysis of case histories of children admitted to hospital with UTI (pyelonephritis, cystitis, non-site specific urinary tract infection) in 1990, 2000, and 2015. We studied the results of triple (in succession) urine cultures. Shedding in a concentration of ≥ 103 cfu/ml for primary pathogens, ≥ 103 cfu/ml in boys and ≥ 104 cfu/ml in girls for secondary pathogens, ≥ 105 cfu/ml for doubtful pathogens considered to be a diagnostically significant one.Results. Members of the family Enterobacteriaceae were the main causative agents of the UTI in 1990 (found in 90.4% of 502 samples), 2000 (in 79.7% of 632 samples), and 2015 (in 67.6% of 801 samples, df = 2, p &lt; 0.001). Escherichia coli remained the most common microorganism, the isolation rate of which decreased from 79.9% in 1990 to 39.5% in 2015 (p &lt; 0.001). In the period from 2000 to 2015, there was a decrease in the frequency of urine detection of Enterobacter spp. (from 5.9 to 2.5%; p &lt; 0.001) and Citrobacter spp. (from 5.2 to 1%; p &lt; 0.001) and, on the contrary, an increase in the isolation rate of Proteus spp. (from 7.8 to 11.7%; p = 0.005), Klebsiella spp. (from 2.8 to 12.9%; p &lt; 0.001) and Enterococcus spp. (from 1.8 to 19.1%; p &lt; 0.001); the latter two — due to more frequent shedding in boys (by 10.5 and 19.9%, respectively).Conclusion. The Enterobacteriaceae members, mainly E. coli and Enterococcus spp., remained the predominant UTI pathogens in children in 1990, 2000, and 2015. The isolation rate of E. coli has declined significantly in recent years, whereas that of Klebsiella spp. and Enterococcus spp. has increased

Intranasal Ion-Triggered In Situ Delivery System of Virus-like Particles: Development Using the Quality by Design Approach

The rapid growth in the prevalence of infectious diseases requires timely action from drug developers. In recent years, the COVID-19 pandemic has demonstrated the unpreparedness of the population for such emergencies. The introduction of modern methods of Design of Experiments (DoE) is required to accelerate the process of drug development and bring a drug to market. The main objective of this study was to develop an ion-triggered in situ system for intranasal delivery of VLP using a Quality by Design approach. Based on a literature review and initial studies, the key QTPP, CQA, CPP, and CMA were identified to develop a novel delivery system for virus-like particles. As a result of the studies on the quality attributes of the developed delivery system, an ion-triggered in situ gel meeting all the specified parameters was obtained using the Quality by Design method