Fig. 2.

CD81 costimulation enhances activation of isolated naive T cells. (A) Isolated naive T cells were activated as indicated for 24 and 48 h. Flow-cytometry plots illustrate change over time of naive (CD62L⁺/CD45RO⁻), CM (CD62L⁺/CD45RO⁺), and EM (CD62L⁻/CD45RO⁺) markers on CD4 and CD8 activated, naive-derived T cells. (B) CD69 expression is shown for CD4 and CD8 isolated naive T cells following 48 h of activation (time point of retroviral transduction). These data are representative of four experiments with average CD69 expression prior to CAR transduction across experiments illustrated. For activation, we employed the nonparametric Friedman test and exact test for repeated-measures experiments. Our null hypothesis (H₀) is that there is no difference in median activation between groups. Our data reject the null hypothesis, indicating a statistically significant difference in activation (P = 0.038) for cells treated with additional CD81 costimulation.