A clinical case of post-COVID-19 myoendocarditis and arrhythmic syndrome at the outpatient stage

Background: Infection with the SARS-CoV-2 virus entails the development of complications which affect the prognosis of the underlying disease. More than 40% of COVID-19 complications represent diseases of the cardiovascular system, most of which are the rhythm and conduction disturbances. In order to avoid these complications, it is necessary to detect cases of infection in a timely manner at the outpatient stage. Clinical case description: A 40-year-old patient came to the clinic with complaints of interruptions in the heart rhythm that appeared after the coronavirus infection. The laboratory examination (CBC) revealed signs of systemic inflammation (leukocytosis 12.6×109 U/l; erythrocyte sedimentation rate 18 mm/h, C-reactive protein 18 mg/l); the instrumental examination of the heart revealed the rhythm disturbances in the form of frequent ventricular ectopic activity and weakness of the SA node. The patient received propafenone (150 mg, 3 times a day) as a therapy with a positive effect. Against the background of improvement in the patient’s condition and despite the history of myocarditis and a positive result of enzyme immunoassay for antibodies to SARS-CoV-2 (IgG, 10 BAU/ml), the patient was prescribed immunization with the CoviVac vaccine. After the immunization, the condition worsening was observed in the form of an increase in the rhythm disturbances, which required an inpatient treatment. A clinical diagnosis of recurrent ventricular arrhythmia — ventricular extrasystole was established, and the therapy was corrected. The outcome was favorable. Conclusion: Myocarditis is one of the most common complications of SARS-CoV-2 and should be kept in mind at all stages of medical care. This clinical case demonstrates the importance of the correct diagnosis and treatment of post-COVID myocarditis, as well as the need to assess contraindications for SARS-CoV-2 vaccination in patients with cardiac complications

Comparative Immunogenicity of the Recombinant Receptor-Binding Domain of Protein S SARS-CoV-2 Obtained in Prokaryotic and Mammalian Expression Systems

The receptor-binding domain (RBD) of the protein S SARS-CoV-2 is considered to be one of the appealing targets for developing a vaccine against COVID-19. The choice of an expression system is essential when developing subunit vaccines, as it ensures the effective synthesis of the correctly folded target protein, and maintains its antigenic and immunogenic properties. Here, we describe the production of a recombinant RBD protein using prokaryotic (pRBD) and mammalian (mRBD) expression systems, and compare the immunogenicity of prokaryotic and mammalian-expressed RBD using a BALB/c mice model. An analysis of the sera from mice immunized with both variants of the protein revealed that the mRBD expressed in CHO cells provides a significantly stronger humoral immune response compared with the RBD expressed in E.coli cells. A specific antibody titer of sera from mice immunized with mRBD was ten-fold higher than the sera from the mice that received pRBD in ELISA, and about 100-fold higher in a neutralization test. The data obtained suggests that mRBD is capable of inducing neutralizing antibodies against SARS-CoV-2

Are Hamsters a Suitable Model for Evaluating the Immunogenicity of RBD-Based Anti-COVID-19 Subunit Vaccines?

Currently, SARS-CoV-2 spike receptor-binding-domain (RBD)-based vaccines are considered one of the most effective weapons against COVID-19. During the first step of assessing vaccine immunogenicity, a mouse model is often used. In this paper, we tested the use of five experimental animals (mice, hamsters, rabbits, ferrets, and chickens) for RBD immunogenicity assessments. The humoral immune response was evaluated by ELISA and virus-neutralization assays. The data obtained show hamsters to be the least suitable candidates for RBD immunogenicity testing and, hence, assessing the protective efficacy of RBD-based vaccines

Structure- and Interaction-Based Design of Anti-SARS-CoV-2 Aptamers

Aptamer selection against novel infections is a complicated and time-consuming approach. Synergy can be achieved by using computational methods together with experimental procedures. This study aims to develop a reliable methodology for a rational aptamer in silico et vitro design. The new approach combines multiple steps: (1) Molecular design, based on screening in a DNA aptamer library and directed mutagenesis to fit the protein tertiary structure; (2) 3D molecular modeling of the target; (3) Molecular docking of an aptamer with the protein; (4) Molecular dynamics (MD) simulations of the complexes; (5) Quantum-mechanical (QM) evaluation of the interactions between aptamer and target with further analysis; (6) Experimental verification at each cycle for structure and binding affinity using small-angle X-ray scattering, cytometry, and fluorescence polarization. Using a new iterative design procedure, Interaction Based Drug Design (SIBDD), a highly specific aptamer to the receptor-binding domain of the SARS-CoV-2 spike protein, was developed and validated. The SIBDD approach enhances speed of the high-affinity aptamers development from scratch, using a target protein structure. The method could be used to improve existing aptamers for stronger binding. This approach brings to an advanced level the development of novel affinity probes, functional nucleic acids. It offers a blueprint for the straightforward design of targeting molecules for new pathogen agents and emerging variants.peerReviewe