(a) Representative flow cytometry plots showing the CAR expression in human T cells transduced with retroviral vectors encoding CD19.28ζ, GD2.28ζ, GD2.28.BBζ, or GD2.28ζ/B7-H3.28ζ CARs. Representative of six independent experiments. (b,c) Representative flow cytometry plots (b) and quantification of residual CHLA-255 cells (c) labelled with GFP co-cultured with CAR-T cells at the T cell to tumor cell ratio of 1 to 5. Data are shown as individual values and the mean ± SD, n = 6 or 8 independent co-cultures using CAR-T cells generated from 6 or 8 different donors. (d,e) Summary of IFN-γ (d) and IL-2 (e) released by CAR-T cells in the culture supernatant after 24 hours of co-culture with NB cells as measured by ELISA. Data are shown as individual values and the mean ± SD, n = 6 or 8 independent co-cultures using CAR-T cells generated from 6 or 8 different donors; **p = 0.0011, ****p <0.0001 by one-way ANOVA with Tukey’s multiple comparison test adjusted p value.