Fig. 1

Preclinical evaluation of BM38 CAR-Ts. a Schematic structure of single-target BCMA CAR, CD38 CAR, bispecific 38BM CAR and BM38 CAR. All the CARs contained a granulocyte–macrophage colony-stimulating factor signal peptide (GM-CSF SP), a CD8 hinge and transmembrane domain, a 4-1BB costimulatory domain and a CD3ζ signaling domain. b CAR expression on lentivirus-transduced T cells and CD38 expression on CAR-Ts. Histograms are representative of 3 independent experiments. NT, nontransduced T. NT blank, NT without antibody staining. NT parallel, NT with antibody staining. c Phenotypic profiles of the final CAR-T products and NT cells. Differentiation phenotypes are depicted for naïve (CD45RA⁺CD62L⁺), central memory (CM) (CD45RA⁻CD62L⁺), effector memory (EM) (CD45RA⁻CD62L⁻) and effector (CD45RA⁺CD62L⁻) cells. n = 3, mean ± standard error of mean (SEM). Statistical analysis was performed using one-way ANOVA and subsequent multiple comparisons with BM38 CAR-Ts. ***P < 0.001; ns: not significant. d Expansion curves of the four CAR-Ts and NT cells after lentiviral transduction. n = 5, mean ± SEM. Repeated measures one-way ANOVA was used, ns: not significant. e Cytotoxicity of the four CAR-Ts and NT cells to target cells at an effector: target (E:T) ratio of 1:1, 5:1 and 10:1. n = 4, mean ± SEM. Dunnett’s multiple comparisons test was used at every E:T ratio with BM38 CAR-Ts as the control. *P < 0.05; **P < 0.01; ***P < 0.001; ns: not significant. f Production of interferon γ (IFNγ) at an E:T ratio of 1:1. n = 3, mean ± SEM. Dunnett’s multiple comparisons test was used with BM38 CAR-Ts as control. **P < 0.01; ***P < 0.001; ns: not significant. g Luciferase live imaging of MM.1s xenograft mice on day 0, 7, 14 and 23 after infusion of 3.0 × 10⁶ NT cells, BCMA CAR-Ts, 38BM CAR-Ts or BM38 CAR-Ts. h Kaplan–Meier survival plot of MM xenograft mice. The log-rank test was used