We measured serum cytokines 24 h after amph-FITC injection on day 3 and day 12 following E2-28z CAR T cell transfer in the CT-2A tumour model, and saw no elevation of inflammatory cytokines, with the exception of a low level of IFN-γ at day 3 (Extended Data Fig. 4c). This evidence concerns the gene IFNG and neoplasm.