Fig. 4: Phenotypic analysis of M198–206-specific CD8+ T cells in PBMC.
Flow cytometric analysis of M198–206-specific CD8+ T cells. a Representative data of M198–206 tetramer staining of PBMC from moderate COVID-19 convalescents. b The frequencies of tetramer-positive cells were compared among indicated groups (healthy donors (HC), n = 6; mild, n = 12; moderate, n = 8; severe, n = 10). Data represent mean + SD. p values were calculated by a two-sided Mann–Whitney test. **p = 0.0073, *p = 0.024. c Subsets of M198–206-specific CD8+ T cells from COVID-19 convalescents (n = 13; 7 moderate and 6 severe subjects) were analyzed based on CD45RA and CCR7 staining. p values were calculated by two-sided Wilcoxon matched-pairs signed rank test. *p = 0.047 (naive-CM), 0.031 (CM-EM), and 0.031 (naive-EM) for moderate; *p = 0.69 (naive-CM), 0.31 (CM-EM), and 0.19 (naive-EM) for severe. d, e The frequency of PD-1 (d) and CD57 (e) positive cells were compared between total CD8+ T cells (Total CD8+) and M198–206-MHC tetramer+ CD8+ T cells (Tet+ CD8+) in moderate (n = 7) and severe (n = 6) groups. p values were calculated by two-sided Wilcoxon matched-pairs signed rank test. ns = not significant, *p = 0.031 for (d); *p = 0.031, 0.031 for e. f Time-course study of the frequency of M198–206-specific CD8+ T cells in COVID-19 convalescents. g The frequency of M198–206 tetramer-positive cells among moderate/severe COVID-19 convalescents of pre-SARS-CoV-2-Omicron and post-SARS-CoV-2-Omicron pandemic. p values were calculated by two-sided Mann–Whitney test. Data represent mean + SD (n = 18, and 6 for Pre-Omicron and Post-Omicron, individually).
