Figure 3.
IL13BBζ T Cells Mediate Superior Anti-tumor Efficacy as Compared to First-Generation IL13ζ T Cells
ffLuc+ PBT030-2 cells (1 × 105) were stereotactically implanted into the right forebrain of NSG mice. On day 8 (A–D) or day 5 (E and F), mice (n = 6 or 7 per group) received either no treatment (PBT030-2); ICT treatment with 1.6 × 106 mock-transduced T cells (Mock); 0.1 × 106, 0.3 × 106, or 1.0 × 106 IL13ζ CD8+ clone 2D7 cells; or 0.1 × 106, 0.3 × 106, or 1.0 × 106 CAR+ IL13BBζ T cells (1.0 × 106 CAR+ = 1.6 × 106 total T cells; 63% CAR+). (A) Representative mice from each group showing relative tumor burden over time using Xenogen Living Image. T cell infusion on day 8 is indicated by the vertical dotted line. (B) Linear regression lines of the natural log of ffLuc flux (photons/s) for each group over time. T cell infusion on day 8 is indicated by the dotted vertical line, and means ± SE are depicted at each time point. (C) Quantification of ffLuc flux on day 27. Each data point represents an individual mouse, and lines indicate median values. p = 0.046 when comparing mice treated with 1.0 × 106 IL13ζ CD8+ clone 2D7 to those treated with 0.1 × 106 CAR+ IL13BBζ T cells using an unpaired Student’s t test. (D) Kaplan-Meier survival analysis demonstrating improved survival for mice treated with IL13BBζ T cells. T cell infusion on day 8 is indicated by the dotted vertical line. *p = 0.048; **p ≤ 0.005 when compared to mice treated with mock-transduced T cells using the log rank (Mantel-Cox) test. (E) Representative 20× immunohistochemical images of brains collected from mice 6 days after ICT treatment with 1.0 × 106 IL13ζ CD8+ clone 2D7 cells or CAR+ IL13BBζ T cells (1.0 × 106 CAR+ = 3.0 × 106 total T cells; 33% CAR+) and stained for CD3+ T cells. Sites of tumor (left), leptomeninges (LM, center), and corpus callosum (CC, right) each with 100 μm scale bars are depicted. LV, lateral ventricle; CP, choroid plexus; EL, ependymal lining. (F) Average CD3 cell counts (±SD) from either the whole-brain section (top) or tumor-containing field (bottom) were determined from the experiment described in (E) using two brains per group and three sections per brain. *p = 0.0008; **p = 0.0099 when compared to mice treated with IL13BBζ T cells using an unpaired Student’s t test.