Figure 4.

P4-10bbz CAR T cells control GFRα4-expressing tumors in vivo

(A and B) NSG mice were implanted subcutaneously with 5 × 10⁶ TT cells engineered to express click beetle green luciferase (CBG). On day 9 post-TT cell implantation, mice received 1 × 10⁷ T cells expressing no CAR (NTD, n = 7) or P4-10bbz (n = 8). Tumor burden was assessed by bioluminescence imaging (A) and by caliper measurement (B). Each line in (A) represents an individual mouse, and curves in (B) represent mean volumes; error bars indicate 1 standard deviation. (C) On day 21 after TT injection, peripheral blood human T cells were counted by flow cytometry (*p < 0.05, Student’s t test). (D) NSG mice were injected intravenously with 2 × 10⁶ Nalm6 cells engineered to express CBG and GFRα4. Five days later, mice were injected intravenously with 2 × 10⁶ control T cells (NTD, n = 10), 19bbz (n = 10), or P4-10bbz (n = 10) CAR T cells, and tumor burden was assessed by bioluminescent imaging (*p < 0.05, 1-way ANOVA, Dunnett’s multiple comparisons test compared to NTD). (E) On days 13 and 20 after T cell injection, peripheral blood human T cells were counted by flow cytometry (*p < 0.05, ANOVA, Tukey’s multiple comparisons test). All error bars indicate 1 standard deviation of the mean.