ABSTRACT
Severe course of COVID-19 is largely determined by hyperactivation of the immune system, or cytokine storm, in which immune cells (lymphocytes, monocytes, etc.) play a major role. Using low-voltage scanning electron microscopy, we studied the morphology of lymphocytes and monocytes during cytokine storm. Monocytes and lymphocytes were isolated by fluorescence sorting from the blood of healthy volunteers (n=6) and patients with COVID-19 (n=5) during cytokine storm (IL-6>23 ng/ml, smear positive for SARS-CoV-2). For each patient, 11-32 individual cells were analyzed at magnification of 18-32,000 times. Measurements showed that monocyte size was increased during cytokine storm (p=0.0001).
Subject(s)
COVID-19 , Humans , Monocytes , SARS-CoV-2 , Cytokine Release Syndrome , Microscopy, Electron, Scanning , Cytokines , Lymphocytes , ElectronicsABSTRACT
We studied the differences in the characteristics of T-cell immunity in clinically healthy volunteers of three groups: "no previous COVID-19, not vaccinated", "recovered", and "vaccinated" as well as the relationship between the presence of IFNγ-releasing T cells in response to stimulation with peptide pools overlapping the main S, N, M, ORF3, and ORF7 protein sequences and the presence of IgG to the SARS-CoV-2 S protein. In the "no previous COVID-19, non-vaccinated" group, T cells specific to both S protein and other virus proteins were absent in 95% subjects. In the "recovered from COVID-19" group, T cells specific to the spike protein were present in samples from 39% subjects. In the same group, T-cell immunity to other viral proteins was present in 58% subjects. In vaccinated subjects, specific T cells responding to stimulation with S protein peptides were found in 47% cases and Т cells specific to N, M, ORF3, ORF7 proteins were detected in only 22% subjects.
