Two distinct subpopulations of human stem-like memory T cells exhibit complementary roles in self-renewal and clonal longevity
Fig 2
CD95hi TSCM cells exhibit increased self-renewal and functionality compared to both CD95int TSCM cells and TCM cells.
(A) Self-renewal in response to homeostatic cytokines was investigated by culturing sorted CD95hi, CD95int and TCM for 7 days with 25 ng/ml IL-7/IL-15, 25 ng/mL IL-15 or 6.1 ng of IL-2 (N = 13, 10, 5, respectively). The self-renewal (defined as percentage of divided cells that have maintained their input phenotype) of each subset on day 7 is shown. The self-renewal of CD95hi TSCM was consistently higher than that of CD95int TSCM or TCM in response to all 3 conditions (CD95hi v CD95int: IL-7/IL-15 P = 0.0001, N = 13; IL-15 P = 0.0002, N = 10; IL-2 P = 0.1, N = 5. CD95hi v TCM: IL-7/IL-15 P = 0.0008, N = 13; IL-15 P = 0.1, N = 10; IL-2 P = 0.5, N = 5. Unpaired Wilcoxon, number of independent tests per dataset = 2). (B) Self-renewal in response to TCR stimulation was investigated by culturing sorted T cell subpopulations for 7 days with 25 ng/ml IL-7/IL-15, 2 μg/ml aCD3 and 1 μg/ml aCD28. (C) Multipotency in response to TCR stimulation was investigated by culturing sorted CD95hi, CD95int and TCM for 7 days with 25 ng/ml IL-7/IL-15, 2 μg/ml αCD3 and 1 μg/ml αCD28. The phenotype of the starting (sorted) population is shown in the grey bars above each panel and the subpopulations they differentiated into are plotted. (D) The data from panel C is used to calculate a multipotency index, this captures the diversity in subpopulations that a subpopulation generates and is defined for a subpopulation j as where pi is the proportion of differentiated cells (i.e., those that have changed phenotype) that are represented by subpopulation i. N = 9 but due to low frequencies of some cell populations N = 4 for CD95hi TSCM and N = 7 for TCM. (E) FACS-isolated T cell subsets were stimulated for 12 h with 2 μg/ml αCD3 and 1 μg/ml αCD28. Boxplots on left summarize the percentage of TNFα, IFNγ and IL-2 expressing cells among the different subsets. Boxplot on right shows markers associated with cytotoxicity. N = 5. An extension of panel E to show TN and TEM is shown in Fig E in S1 Text. In all cases bars represents the median, the box the interquartile range (IQR) and whiskers show lower quartile − 1.5 * IQR and upper quartile + 1.5 * IQR; all data points (including outliers) are shown by filled circles. All subjects from Cohort 1. A replicate of this figure but with individuals identified by different symbols is provided in Fig S in S1 Text. The data underlying this figure can be found in S1 Data.