ABSTRACT
Introduction. The COVID-19 pandemic caused by highly contagious SARS-CoV-2 coronavirus is still at its peak. As this infection is being studied, new diagnostic methods are emerging and existing ones are being optimized. The production of antibodies against a variety of SARS-CoV-2 antigens is being intensively studied to understand the basic mechanisms of humoral immunity and protective functions of antibodies. Purpose. To study dynamics of formation and maintenance of antibodies to three main antigens (S, N, M) of SARS-CoV-2 virus. Materials and methods. Seventy-five respondents with COVID-19 infection of different severity took part in the study: mild form – 22 persons, moderate form – 26 persons, severe form – 20 persons. Control group consisted of 7 seronegative sera collected from healthy volunteers. To confirm the presence of antibodies to SARS-CoV-2 virus we used commercial test-systems manufactured by Vector-BEST "SARS-CoV-2-IgG-ELISA-BEST" (Russian Federation);"SARS-CoV-2-NP-ELISA-G" produced by Republican Scientific and Practical Center of Epidemiology and Microbiology (Republic of Belarus);as well as newly developed immunoassay "home-made" lia-test (a nitrocellulose membrane with applied S, N, M antigens of SARS-CoV-2 virus). Results. Nine months after the disease, antibodies to S antigen persisted in 92.6% of respondents with a mild form of the disease, and in 100% of those with moderate and severe forms. The N antigen remains seropositive in 48.1%, 48% and 65% of patients with mild, moderate and severe COVID-19, respectively. Positive tests for M protein are 26%, 44%, and 55% with increasing severity of infection. Conclusion. Production of antibodies to S-, N-, and M-proteins of SARS-CoV-2 virus occurs with regard to individual characteristics of the immune system. By the end of 9 months of follow-up, the respondents with moderate and severe forms of coronavirus infection retained antibodies to S-protein in 100% of cases. For N-and M-proteins, significantly fewer seropositive respondents were detected (48%, 65%, and 44% 55%, respectively). Patients who had a mild form of infection retained antibodies to S, N, and M antigens in 92.6%, 48.1% and 26% of cases, respectively. Thus, antibodies to S-protein of SARS-CoV-2 virus, which, as a rule, is the main antigenic component of commercial test systems, persist in the human body for the longest time. © 2022, Professionalnye Izdaniya. All rights reserved.