Fig. 1.

Human CD26^high T cells are activated and display antitumor activity. CD4⁺ lymphocytes were isolated from healthy donor PBMCs, sorted by CD26 expression and stimulated with magnetic beads coated with CD3 and ICOS agonists (cultured at a ratio of 1 bead to every 5 T cells). T cells were transduced 36 h post-activation with a lentiviral vector encoding a first generation chimeric antigen receptor that recognizes mesothelin and stimulates the CD3ζ domain. These cells were expanded for 10 days with IL-2 (100 IU/ml). a, b NSG mice were subcutaneously injected with 5e⁶ M108 mesothelioma cells. Forty days post-M108 establishment, mice were intravenously infused with 1e⁵ human CD26^neg or CD26^high T cells redirected to express MesoCAR. Tumors were measured bi-weekly (N = 10 mice per group). P values for the tumor curve were calculated by one-way ANOVA with a Kruskal-Wallis comparison using final tumor measurements from day 62. c–g Graphical representations of transcription factors (c–f N = 10) and cytokine production (g N = 3) by sorted T cells isolated from multiple healthy individuals prior to bead stimulation. In g, the frequency of FoxP3⁺ cells from the enriched CD26^neg or CD26^high cultures secreting inflammatory cytokines were assayed by flow cytometry. P values for c-e were calculated using a Mann-Whitney U Test. Data with error bars represent mean ± SEM. *P  < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001