Fig. 8. In vivo anti-leukemia efficacy of DN4.99 TCR-T cells against CD1c+ acute leukemia NALM-6.
DN4.99 TCR-transduced T (DN4.99 TCR-T) cells restrict NALM-6-CD1c leukemia progression in vivo. a NOD.Cg-Prkdcscid IL- 2rgtm1Wjl/SzJ (NSG) mice (n = 30) received intravenous (i.v.) injection of 5 × 105 NALM-6 CD1c co-expressing secreted LUCIA luciferase. Two days later, the mice were sub-lethally irradiated, followed 24 h later by the transfer of 107 primary 70% CD8+/30% CD4+ DN4.99 TCR-T cells (red lines/dots), control T cells (black line/squares) transduced with the CD1c-restricted, mycobacterial lipid-specific DL15A31 TCR (DL153A1 TCR-T cells; Supplementary Fig. 4 and ref. 10) or vehicle (gray lines/triangles). n = 10 mice/group. After 7 days, DN4.99 TCR-T cells were transferred a second time, without prior irradiation, into the same mice. b Tumor progression was monitored in peripheral blood by a bioluminescence assay. RLU, relative light unit. Data are represented as mean ± SEM. ****P < 0.0001 determined on AUC by Ordinary one-way ANOVA followed by Tukey’s multiple comparison test. c DN4.99 TCR-T cells reduce the number of circulating NALM-6-CD1c leukemia cells. The frequency of human CD19+ tumor cells was determined by flow cytometry in the blood of mice at day+17 from tumor injection. The percentage of the tumor cells was normalized based on the percentage of mouse CD45- cells. *P = 0.0101; ***P = 0.0003; ****P < 0.0001. d Presence of DN4.99 TCR-T cells in the bone marrow of NALM-6 CD1c bearing mice, determined by flow cytometry 4 days after their adoptive transfer. DN4.99 TCR-T cells were identified as mouse (m)TCRb+ cells in the human (h)CD45+ mouse (m)CD45- cells. e Kaplan-Meier survival curves show a significant increase in the survival of mice receiving DN4.99 TCR-T cells compared to control groups. **P = 0.0014 determined by log-rank (Mantel–Cox) test. f Reduced CD1c expression on NALM-6-CD1c cells that survive DN4.99 TCR-T cell, as determined by flow cytometry labeling (MFI, Mean Fluorescence Intensity) of human CD19+ NALM-6-CD1c cells in the circulation at day+17 from tumor injection. **P = 0.0015; ****P < 0.0001. Data in (c) and (f) are represented as mean ± SD and P-values were determined by unpaired two-tailed t test followed by Mann–Whitney test. Results are representative of 3 independent experiments with independent T cell lines giving comparable results.