Fig. 4
From: Frailty impacts immune responses to Moderna COVID-19 mRNA vaccine in older adults
T Cell Responsiveness in Frail Older Adults. The flow cytometry AIM assay was used to assess CD4+ and CD8+ T cell responsiveness after stimulation of PBMC from individuals (n = 13) collected 2-weeks post vaccine dose 2 for 24 hrs with pooled spike peptides (0.8μg/mL) or equimolar DMSO negative control. (A) While individuals with prior COVID-19, indicated by a green square (p = 0.055) had a trend towards increased AIM+CD4+ cells, frailty was not a significant predictor (p = 0.13). (B) Prior COVID-19 infection (green square) was positively associated with AIM+CD8+ cells (p = 0.0045), but frailty was not a significant predictor (p = 0.17). (C) Older aged individuals had decreased AIM+ TFH cells (p = 0.011). Representative flow plots with spike and DMSO negative control of (D) CD4+ AIM by mild (blue line) or severe (red line) frailty status, (E) CD8+ AIM by uninfected (black line) or prior COVID-19 (green line), and (F) CD4+ TFH cells, defined by CD4+ CD4 + CXCR5 + PD1+ cells, and AIM defined by OX40 + CD137 +