Immunoliposomes As a Promising Antiviral Agent against SARS-CoV-2

According to the World Health Organization, as of January 3, 2020 to September 13, 2023, there were approximately 23 million confirmed cases of COVID-19 reported in the Russian Federation, about 400 thousand of which were fatal. Considering the high rate of mutation of the RNA-containing virus genome, which inevitably leads to the emergence of new infectious strains (Eris and Pyrola), the search for medicinal antiviral agents remains an urgent task. Moreover, taking into account the actively mutating receptor-binding domain, this task requires fundamentally new solutions. This study proposes a candidate immunoliposomal drug that targets the S protein of SARS-CoV-2 by the monoclonal neutralizing antibody P4A1 and ensures the penetration of a highly active ribonuclease into the virus-infected cell, which degrades, among cellular RNA, viral RNA too. We demonstrate a more than 40-fold increase in the neutralizing activity of the developed drug compared to the free monoclonal neutralizing antibody.

An ELISA Platform for the Quantitative Analysis of SARS-CoV-2 RBD-neutralizing Antibodies As an Alternative to Monitoring of the Virus-Neutralizing Activity

Monitoring of the level of the virus-neutralizing activity of serum immunoglobulins ensures that one can reliably assess the effectiveness of any protection against the SARS-CoV-2 infection. For SARS-CoV-2, the RBD-ACE2 neutralizing activity of sera is almost equivalent to the virus-neutralizing activity of their antibodies and can be used to assess the level of SARS-CoV-2 neutralizing antibodies. We are proposing an ELISA platform for performing a quantitative analysis of SARS-CoV-2 RBD-neutralizing antibodies, as an alternative to the monitoring of the virus-neutralizing activity using pseudovirus or "live" virus assays. The advantage of the developed platform is that it can be adapted to newly emerging virus variants in a very short time (1-2 weeks) and, thereby, provide quantitative data on the activity of SARS-CoV-2 RBD-neutralizing antibodies. The developed platform can be used to (1) study herd immunity to SARS-CoV-2, (2) monitor the effectiveness of the vaccination drive (revaccination) in a population, and (3) select potential donors of immune plasma. The protective properties of the humoral immune response in hospitalized patients and outpatients, as well as after prophylaxis with the two most popular SARS-CoV-2 vaccines in Russia, were studied in detail using this platform. The highest RBD-neutralizing activity was observed in the group of hospitalized patients. The protective effect in the group of individuals vaccinated with Gam-COVID-Vac vaccine was 25% higher than that in outpatients and almost four times higher than that in individuals vaccinated with the CoviVac vaccine.

COVID-19 in Russia: Clinical and Immunological Features of the First-Wave Patients

The coronavirus disease outbreak in 2019 (COVID-19) has now achieved the level of a global pandemic and affected more than 100 million people on all five continents and caused over 2 million deaths. Russia is, needless to say, among the countries affected by SARS-CoV-2, and its health authorities have mobilized significant efforts and resources to fight the disease. The paper presents the result of a functional analysis of 155 patients in the Moscow Region who were examined at the Central Clinical Hospital of the Russian Academy of Sciences during the first wave of the pandemic (February-July, 2020). The inclusion criteria were a positive PCR test and typical, computed tomographic findings of viral pneumonia in the form of ground-glass opacities. A clinical correlation analysis was performed in four groups of patients: (1) those who were not on mechanical ventilation, (2) those who were on mechanical ventilation, and (3) those who subsequently recovered or (4) died. The correlation analysis also considered confounding comorbidities (diabetes, metabolic syndrome, hypertension, etc.). The immunological status of the patients was examined (levels of immunoglobulins of the M, A, G classes and their subclasses, as well as the total immunoglobulin level) using an original SARS-CoV-2 antibody ELISA kit. The ELISA kit was developed using linear S-protein RBD-SD1 and NTD fragments, as well as the N-protein, as antigens. These antigens were produced in the prokaryotic E. coli system. Recombinant RBD produced in the eukaryotic CHO system (RBD CHO) was used as an antigen representing conformational RBD epitopes. The immunoglobulin A level was found to be the earliest serological criterion for the development of a SARS-CoV-2 infection and it yielded the best sensitivity and diagnostic significance of ELISA compared to that of class M immunoglobulin. We demonstrated that the seroconversion rate of "early" N-protein-specific IgM and IgA antibodies is comparable to that of antibodies specific to RBD conformational epitopes. At the same time, seroconversion of SARS-CoV-2 N-protein-specific class G immunoglobulins was significantly faster compared to that of other specific antibodies. Our findings suggest that the strong immunogenicity of the RBD fragment is for the most part associated with its conformational epitopes, while the linear RBD and NTD epitopes have the least immunogenicity. An analysis of the occurrence rate of SARS-CoV-2-specific immunoglobulins of different classes revealed that RBD- and N-specific antibodies should be evaluated in parallel to improve the sensitivity of ELISA. An analysis of the immunoglobulin subclass distribution in sera of seropositive patients revealed uniform induction of N-protein-specific IgG subclasses G1-G4 and IgA subclasses A1-A2 in groups of patients with varying severity of COVID-19. In the case of the S-protein, G1, G3, and A1 were the main subclasses of antibodies involved in the immune response.

"Shielding" of Cytokine Induction by the Periodontal Microbiome in Patients with Periodontitis Associated with Type 2 Diabetes Mellitus

Periodontal diseases, especially those with polymicrobial etiology, are often associated with type 2 diabetes mellitus, proceeding more severely and affecting the course of diabetes mellitus. Recently, this feature has been associated with the ability of periodontopathogen microflora to cause not only a local infectious process in the oral cavity, but also to interact with the human immune system and induce various systemic effects. We investigated changes in the salivary cytokine profile of patients with chronic periodontitis, associated and not associated with type 2 diabetes mellitus. We observed a statistically significant decrease of MCP-1/CCL2, GM-CSF, IL-5, IL-6, and IFN-γ in the saliva of patients with chronic periodontitis associated with type 2 diabetes mellitus in comparison with patients with chronic periodontitis only. All of these cytokines are associated with macrophage activation. These data are an important contribution to the elucidation of the mechanism of periodontopathogens involvement in the manifestation of the systemic effects of type 2 diabetes.

Targeted Drug Delivery in Lipid-like Nanocages and Extracellular Vesicles

The possibility of targeted drug delivery to a specific tissue, organ, or cell has opened new promising avenues in treatment development. The technology of targeted delivery aims to create multifunctional carriers that are capable of long circulation in the patient's organism and possess low toxicity at the same time. The surface of modern synthetic carriers has high structural similarity to the cell membrane, which, when combined with additional modifications, also promotes the transfer of biological properties in order to penetrate physiological barriers effectively. Along with artificial nanocages, further efforts have recently been devoted to research into extracellular vesicles that could serve as natural drug delivery vehicles. This review provides a detailed description of targeted delivery systems that employ lipid and lipid-like nanocages, as well as extracellular vesicles with a high level of biocompatibility, highlighting genetically encoded drug delivery vehicles.

Cloning and characterization of serpin from red king crab Paralithodes camtschaticus

Serpins are a family of serine protease inhibitors that are involved in numerous physiological processes and are known to regulate innate immunity pathways. To advance our understanding of their role in P. camtschaticus, a commercially significant species, we cloned and characterized a serpin from this species, designated serpin PC, that has anticoagulant and anticomplement effects on human blood. We found that serpin PC is a secreted protein with a typical serpin-like primary structure that is similar to other known crustacean serpins. Recombinant serpin PC was found to have inhibitory activity against R/K-specific bovine cationic trypsin. The reaction proceeds through the formation of a stable covalent complex of peptidase with P1 residue R383 of serpin PC. This interaction is characterized by a relatively high overall inhibition constant k_ass=(2.3 ± 0.7) × 10⁶ M^-1s^-1 and an SI of 4.7 ± 0.8. Protein localization by western blotting showed that serpin PC is present in the muscles and, to a lesser extent, the heart, whereas it is transcribed predominantly in hemocytes and the heart. Through peptidase activity profiling of hemocytes and plasma, we found that serpin PC inhibits at least two R/K-specific activities and showed that it inhibits phenoloxidase (PO) activity induction in hemocytes.

Generation of Highly Specific Proteolytic Biocatalysts by Screening Technologies

We propose a yeast display-based system for screening of proteolytic enzyme libraries that utilizes substrate protein adsorbed on the yeast cell surface and containing a desired cleavage sequence. Specific cleavage of the substrate protein releases its biotin-binding center. The cells carrying the target proteinase can be selected by cytofluorometry due to interaction with biotinylated fluorescent protein. Using human enterokinase light chain as the model proteinase we showed that the proposed screening system highly effectively selects the proteolytic enzymes with preset specificity.

Preparation of Recombinant Serpin from Red King Crab Paralithodes сamtschaticus for Biomedical Research Purposes

Genetic constructs with different leader sequences for intra- and extracellular expression of the target protein were generated and an original method for effective selection of clones with maximum expression was developed. For intracellular expression in the Pichia pastoris system, seprin content in cells was 6 mg/liter.

[Microcontroller temperature regulator MPT110 for drying-sterilizing cabinets]

The paper describes a MPT-110 temperature microcontroller developed by the closed joint-stock company "OPLEKS" (Orel, Russia) and the results of comparative tests performed in the @IIICC-80 drying sterilizing cabinet. The use of the MPT-110 controller is shown to improve the quality of control and to shorten the times that is taken for the cabinet to reach the preset temperature point.