The Evaluation of the Intensity of Cellular and Humoral Immunity to COVID-19 Causative Agent in Moscow Residents

The aim of the research is to estimate the levels of cellular and humoral immunity to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among Moscow residents over 18 years old. During the study, participants will be divided into four groups: healthy volunteers; individuals recovered from coronavirus disease 2019 (COVID-19) with different severity; individuals vaccinated against SARS-CoV-2; individuals who have had COVID-19 concomitantly with comorbidities that characterized by the impact on the immune system (tuberculosis, chronic obstructive pulmonary disease, HIV infection, hematological neoplasia). For all participants included into the study peripheral blood will be collected and the titers of SARS-CoV-2 specific immunoglobulins M (IgM) and immunoglobulins G (IgG), frequencies of the T cells specific to nucleocapsid (N), membrane (M), and spike (S) proteins of SARS-CoV-2 in peripheral blood, as well as the fractions of virus specific T helpers and cytotoxic T cells will be estimated. For smaller cohorts of the participants in all groups the antibody titers and T cell response levels will be examined in dynamics. All participants will be monitored for the incidence of primary or repeated COVID-19 for 1-2 years after inclusion in the study.

Based on the results of the study, the relationship between the formation of humoral and cellular immunity against COVID-19, the duration of these types of immunity, as well as their individual contribution to protection against primary or secondary SARS-CoV-2 infection will be analyzed. Additionally, data concerning patients recovered from COVID-19 and having concomitant diseases will provide a valuable information that may help to understand in more details the mechanisms of the development of the SARS-CoV-2 specific immune response.