Figure 2.

Lower activating signal strength programs an optimal T cell memory phenotype

(A) Cell division over 1 week of culture. CFSE-labeled cells were activated with either CD3/CD28 (black and blue) or CD3/ICOS (purple and red) beads at two different ratios: 3:1 bead:T cell and 1:10 bead:T cell. Cells from each culture were collected and fixed each day after activation, up to 7 days. After 7 days, all cells were analyzed via flow cytometry. (B) Cell growth rate was also observed. Cells from each culture were counted every other day, up to day 10 of culture (n = 3). (C–F) After 10 days of growth, expression of memory markers and coinhibitory receptors was analyzed by flow cytometry. Numbers in the fluorescence-activated cell sorting (FACS) plots represent percentage of positive lymphocytes. Bar graphs represent the mean ± SEM. Statistical analysis was performed using one-way ANOVA with Tukey’s multiple comparisons test (n = 7, ∗p < 0.05, ∗∗p < 0.01).