ABSTRACT
Cellular immunity plays an important role in the pathogenesis and formation of protective immune defense against the SARS-CoV-2 virus. The aim of the work was to study the cellular immunity of rhesus monkeys applying flow cytometry after experimental infection with the SARS-CoV-2 virus. Materials and methods. Male rhesus monkeys were intranasally inoculated with the SARS-CoV-2 virus, Isolate B strain and hCoV-19/Russia/SP48-1226/2020 strain (abbreviated name U-2), at a dose of 5.0 lg PFU. Using flow cytometry, the levels of 21 populations/subpopulations of mononuclear cells in the peripheral blood of animals were determined before experimental infection with the pathogen and on day 14 after infection. SARS-CoV-2 coronavirus RNA was assessed using real-time polymerase chain reaction. Determination of the titer of virus-neutralizing antibodies to the SARS-CoV-2 virus in the blood sera of animals was conducted through neutralization test evaluating the ability to suppress negative colonies. Results and discussion. Infection with Isolate B strain culture has led to an increase in the relative content of total T-lymphocytes (p<0.2), cytotoxic T-lymphocytes (p<0.1), as well as monocytes expressing the early activation marker CD25 (p<0.2). The decrease in levels has been observed for total B-lymphocytes (p<0.2) and T-helper cells (p<0.1). Infection with the U-2 strain culture revealed an increase in the relative content of monocytes expressing the early activation marker CD25 (p<0.2). Thus, for the first time in the Russian Federation, flow cytometry was used to study the cellular immunity of rhesus monkeys before and after experimental infection with the SARS-CoV-2 virus. The obtained information can be used for studying the pathogenesis of SARS-CoV-2 infection, course, and outcome of the disease, and developing strategies for vaccination and treatment. © 2022 Russian Research Anti-Plague Institute. All rights reserved.