Two distinct subpopulations of human stem-like memory T cells exhibit complementary roles in self-renewal and clonal longevity
Fig 10
A population of YFV-specific cells enriched for CD95int TSCM declines much more slowly over time than a population enriched for CD95hi TSCM.
Here we reproduce the analysis from Fuertes Marraco and colleagues [2] who investigated the decline of YFV-specific memory subpopulations with time post-vaccination in a cross-sectional cohort. Fuertes Marraco and colleagues note that there is large between-individual variation in the sizes of CD8+ memory subpopulations and that this noisy interindividual variation can be reduced by quantifying the frequency of YFV-specific cells within each subpopulation rather than within the total CD8+ population (e.g., quantify YFV-specific TCM CD8+ cells as a percent of total TCM rather than as a percent of total CD8+ T cells) (A). Analysis of the raw data shows that a proxy for YFV-specific CD95int TSCM cells (YFV-specific “naïve hi” cells) – left panel – decline significantly more slowly than a proxy for YFV-specific CD95hi TSCM cells (YFV-specific “naïve int” cells) – right panel (P = 0.039, linear regression). The blue and orange lines are the best fit straight lines to the CD95int and CD95hi TSCM data, respectively. (B). Analysis in Fuertes Marraco and colleagues [2] differs slightly in that they chose to exclude three individuals with very low frequencies of YFV-specific CD8+ T cells and to include 4 individuals who had received multiple YF vaccinations. Our conclusions are robust to these two steps (if anything they appear to strengthen the conclusion that YFV-specific CD95int TSCM cells decline more slowly than YFV-specific CD95hi TSCM cells). Recipients of multiple vaccinations shown by open symbols.