Fig. 1
From: SARS-CoV-2 spike-specific TFH cells exhibit unique responses in infected and vaccinated individuals
Longitudinal analysis of TFH cell and subset responses in COVID-19 convalescents. a Timeline of blood sample collection from COVID-19 convalescents. The median and interquartile range (IQR) of days of sampling and number of samples are shown for each time point. b Representative flow plots of spike-specific TFH cells (CD154+) upon BSA or spike protein stimulation. c Spike-specific TFH cell, CXCR3+ TFH cell, and CXCR3− TFH cell responses in COVID-19 convalescents at 2 months (n = 18), 5 months (n = 17), 8 months (n = 18), 12 months (n = 19), and 24 months (n = 5) after illness onset as well as in healthy controls (n = 14), upon stimulation. Paired t test was used to analyze the differences between the responses to BSA and spike protein stimulation. d Kinetics of spike-specific TFH cell, CXCR3+ TFH cell, and CXCR3− TFH cell responses (data presented with background subtracted; responses below background are shown as 0.001%) in COVID-19 convalescents at 2 months (n = 18), 5 months (n = 17), 8 months (n = 18), 12 months (n = 19), and 24 months (n = 5) after illness onset. Data are presented as the mean ± SEM. Mann–Whitney U test was used to analyze differences between the indicated time points. For (c, d), *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001. P < 0.05 was considered to be a two-tailed significant difference, ns, not significant. e Percentage of spike-specific TFH cell, CXCR3+ TFH cell, and CXCR3− TFH cell responders (stimulation index > 2 was considered to be a positive response) among COVID-19 convalescents at 2 months (n = 18), 5 months (n = 17), 8 months (n = 18), 12 months (n = 19), and 24 months (n = 5) after illness onset
