[Increased LAMP1 Expression Enhances SARS-CoV-1 and SARS-CoV-2 Production in Vero-Derived Transgenic Cell Lines].

Coronaviridae is a family of single-stranded RNA (ssRNA) viruses that can cause diseases with high mortality rates. SARS-CoV-1 and MERS-CoV appeared in 2002-2003 and 2012, respectively. A novel coronavirus, SARS-CoV-2, emerged in 2019 in Wuhan (China) and has caused more than 5 million deaths in worldwide. The entry of SARS-CoV-1 into the cell is due to the interaction of the viral spike (S) protein and the cell protein, angiotensin-converting enzyme 2 (ACE2). After infection, virus assembly occurs in Golgi apparatus-derived vesicles during exocytosis. One of the possible participants in this process is LAMP1 protein. We established transgenic Vero cell lines with increased expression of human LAMP1 gene and evaluated SARS-CoV-1 and SARS-CoV-2 production. An increase in the production of both viruses in LAMP1-expressing cells when compared with Vero cells was observed, especially in the presence of trypsin during infection. From these results it can be assumed that LAMP1 promotes SARS-CoV-1 and SARS-CoV-2 production due to enhanced exocytosis.

Immunogenicity and protectivity of the peptide vaccine against SARS-CoV-2

Background. In 2020, the pandemic caused by novel coronavirus infection has become one of the most critical global health challenges during the past century. The lack of a vaccine, as the most effective way to control the novel infection, has prompted the development of a large number of preventive products by the scientific community. We have developed a candidate vaccine (EpiVacCorona) against novel coronavirus infection caused by SARS-CoV-2 that is based on chemically synthesized peptides conjugated to a carrier protein and adsorbed on aluminum hydroxide and studied the specific activity of the developed vaccine. Aims — study of the immunogenicity and protectivity of the peptide candidate vaccine EpiVacCorona. Methods. The work was performed using standard molecular biological, virological and histological methods. Results. It was demonstrated that EpiVacCorona, when administered twice, spaced 14 days apart, to hamsters, ferrets, and non-human primates (african green monkeys, rhesus macaques) at a dose of 260 μg, which is equal to one inoculation dose for humans, induces virus-specific antibodies in 100% of the animals. Experiments in hamsters showed this vaccine to be associated with the dose-dependent immunogenicity. The vaccine was shown to accelerate the elimination of the virus from the upper respiratory tract in ferrets and prevent the development of pneumonia in hamsters and non-human primates following a respiratory challenge with novel coronavirus. Conclusions. The results of a preclinical specific activity study indicate that the use of EpiVacCorona has the potential for human vaccination. © 2021 Izdatel'stvo Meditsina. All rights reserved.

A SINGLE BLIND, PLACEBO-CONTROLLED RANDOMIZED STUDY OF THE SAFETY, REACTOGENICITY AND IMMUNOGENICITY OF THE "EPIVACCORONA" VACCINE FOR THE PREVENTION OF COVID-19, IN VOLUNTEERS AGED 18-60 YEARS (PHASE I-II)

Vaccination of the population is one of the most effective countermeasures in responding to the pandemic caused by novel coronavirus infection. Therefore, scientists all over the world have been working to develop effective and safe vaccines. We have developed a synthetic peptide vaccine, EpiVacCorona, against novel SARS-CoV-2 coronavirus, which is a suspension for intramuscular administration containing a composition of chemically synthesized peptide immunogens of the S protein of SARS-CoV-2 coronavirus conjugated to a carrier protein and adsorbed on aluminum hydroxide. Phase I-II clinical trials of the vaccine have started that consist of two stages: Stage 1 is an open study of the safety, reactogenicity, and immunological activity of the vaccine with the involvement of 14 volunteers aged 18-30 years;Stage 2 is a single blind, comparative, randomized placebo-controlled study with the involvement of 86 volunteers. The study involved volunteers aged 18-60 years;the vaccine was injected intramuscularly twice, spaced 21 days apart between injections. All local reactions in response to vaccine administration were mild, such as a short-term pain at the injection site. There were no signs of development of local or systemic adverse reactions. The two-dose vaccination scheme induced the production of antibodies, specific to the antigens that make up the vaccine, in 100% of the volunteers. Seroconversion with a neutralizing antibody titer >= 1:20 was reported in 100% of the volunteers 21 days following the second immunization dose. No seroconversion was reported in the groups of volunteers vaccinated with a placebo. The peptide-based EpiVacCorona Vaccine has low reactogenicity and is a safe, immunogenic product.

Detection of SARS-CoV-2 RNA in nasopharyngeal swabs from COVID-19 patients and asymptomatic cases of infection by real-time and digital PCR.

In this work we tested two reagent kits developed by us for detecting SARS-CoV-2 RNA using a fragment of the ORF1ab gene in digital PCR and real-time PCR formats. Data were obtained on the detection of SARS-CoV-2 virus RNA in nasopharyngeal swabs of patients with COVID-19 and asymptomatic carriers. The developed reagent kits provided 100% sensitivity and a detection limit of 103 GE / ml for qPCR, and at least 200 copies / ml of viral RNA when performing digital PCR. These methods were tested using a panel of 1,328 samples collected from patients with suspected COVID-19 at the beginning of 2020 in the Russian Federation. It has been shown that dPCR is more sensitive and can be used to analyze samples with low viral load, including those from patients without clinical symptoms. dPCR significantly improves the accuracy of laboratory research and significantly reduces the number of false negative results in the diagnosis of SARS-CoV-2. Determination of the concentration of SARS-CoV-2 RNA in patients with different clinical course of the disease showed that the concentration of viral RNA can sharply decrease in the first days of the disease. A low concentration of viral RNA in samples from patients is also characteristic of asymptomatic disease. Digital PCR provides a higher detection rate for asymptomatic cases, which is approximately 75% of those infected, as opposed to 45% for real-time PCR. The results obtained on the use of the digital PCR method for detecting SARS-CoV-2 RNA showed that this method is especially suitable for detecting RNA in case of its low concentration in contacts, as well as for monitoring changes in viral load in convalescent patients.