Figure 2.
TIGIT blockade improves MM patient CD8+T-cell effector functions and protects mice against MM. (A-B) C57BL/6 WT and Tigit−/− mice were challenged IV with 2 × 106 Vk12653 MM cells. M-protein levels were determined (A) by serum electrophoresis at week 6 post-MM cell injection; (B) survival was monitored overtime. Data are pooled from 2 independent experiments with n = 17 to 19 mice per group. (C) C57BL/6 WT and Tigit−/− mice were challenged IV with 4 × 105 Vk12598 MM cells and monitored for survival. Data shown are from 1 experiment representative of 2, with n = 10 to 12 mice per group. (D-F) C57BL/6 WT and Tigit−/− mice were challenged IV with 1.6 × 106 Vk12653 cells on day 0 and treated with anti-CD8β mAbs or cIg (100 μg, IP) on days −1, 0, 7, 14, 21, and 28. At week 4 after MM inoculation, M-protein levels were determined by serum electrophoresis and myeloma burden in (E) spleen and (F) BM was determined by flow cytometry by gating on B220−CD138+CD155+ MM cells. Data are from 1 experiment with n = 10 mice per group. (G,H) C57BL/6 WT mice were challenged with 1.5 × 106 (triangles) or 2.0 × 106 (circles) Vk12653 MM cells, treated with anti-TIGIT mAbs or cIg (200 μg, IP) twice per week for 4 weeks. Graphs showing the (G) serum γ-globulin levels and (H) number of BM MM cells. Data are presented from 3 independent experiments with n = 29 per group. (I-J) C57BL/6 WT were challenged with 4 × 105 Vk12598 MM cells, treated with anti-TIGIT mAbs, anti-PD-1 mAbs, or cIg (200 μg, IP) twice per week for 4 weeks and monitored for survival. (I) Data are pooled from 3 independent experiments with n = 19 to 30 mice per group. (J) Mice were treated with anti-CD8β mAbs or cIg (100 μg) days −1, 0, 7, 14, 21, and 28 (n = 11 to 12 per group). (K) C57BL/KaLwRijHsd mice (n = 5 per group) were challenged with 2 × 106 5TGM1 MM cells, treated with anti-TIGIT mAbs or cIg (200 μg, IP) twice per week for 4 weeks and monitored for survival. (L) MM patient CD138− BM cells were stimulated by anti-CD3/CD28/CD2 microbeads for 6 hours in the presence of anti-TIGIT mAbs (10 μg/mL) or cIg. Graphs showing the frequencies of TNFα-, IFNγ-, and CD107a-positive CD8+ T cells (n = 16 MM patients). (M) Graphs showing the concentrations of the indicated cytokines in the supernatants of purified MM patient BM CD8+ T cells stimulated by anti-CD3/CD28/CD2 microbeads for 24 hours in the presence of anti-TIGIT mAbs (10 μg/mL) or cIg (n = 11 patients with MM). (A,D-H) Data are presented as mean ± SEM, with each symbol representing an individual mouse. Statistical differences between multiple group were determined by 1-way ANOVA (D-F) with Tukey posttest analysis; differences between 2 groups were assessed using a (A) Mann-Whitney U, 2-way ANOVA (G-H), or (L-M) Wilcoxon matched-pairs signed rank test; (B-C,I-K) Differences in survival were determined by log-rank sum test. *P < .05; **P < .01, ***P < .001, ****P < .0001. cIg, control immunoglobulin; IP, intraperitoneal.

TIGIT blockade improves MM patient CD8+T-cell effector functions and protects mice against MM. (A-B) C57BL/6 WT and Tigit−/− mice were challenged IV with 2 × 106 Vk12653 MM cells. M-protein levels were determined (A) by serum electrophoresis at week 6 post-MM cell injection; (B) survival was monitored overtime. Data are pooled from 2 independent experiments with n = 17 to 19 mice per group. (C) C57BL/6 WT and Tigit−/− mice were challenged IV with 4 × 105 Vk12598 MM cells and monitored for survival. Data shown are from 1 experiment representative of 2, with n = 10 to 12 mice per group. (D-F) C57BL/6 WT and Tigit−/− mice were challenged IV with 1.6 × 106 Vk12653 cells on day 0 and treated with anti-CD8β mAbs or cIg (100 μg, IP) on days −1, 0, 7, 14, 21, and 28. At week 4 after MM inoculation, M-protein levels were determined by serum electrophoresis and myeloma burden in (E) spleen and (F) BM was determined by flow cytometry by gating on B220−CD138+CD155+ MM cells. Data are from 1 experiment with n = 10 mice per group. (G,H) C57BL/6 WT mice were challenged with 1.5 × 106 (triangles) or 2.0 × 106 (circles) Vk12653 MM cells, treated with anti-TIGIT mAbs or cIg (200 μg, IP) twice per week for 4 weeks. Graphs showing the (G) serum γ-globulin levels and (H) number of BM MM cells. Data are presented from 3 independent experiments with n = 29 per group. (I-J) C57BL/6 WT were challenged with 4 × 105 Vk12598 MM cells, treated with anti-TIGIT mAbs, anti-PD-1 mAbs, or cIg (200 μg, IP) twice per week for 4 weeks and monitored for survival. (I) Data are pooled from 3 independent experiments with n = 19 to 30 mice per group. (J) Mice were treated with anti-CD8β mAbs or cIg (100 μg) days −1, 0, 7, 14, 21, and 28 (n = 11 to 12 per group). (K) C57BL/KaLwRijHsd mice (n = 5 per group) were challenged with 2 × 106 5TGM1 MM cells, treated with anti-TIGIT mAbs or cIg (200 μg, IP) twice per week for 4 weeks and monitored for survival. (L) MM patient CD138− BM cells were stimulated by anti-CD3/CD28/CD2 microbeads for 6 hours in the presence of anti-TIGIT mAbs (10 μg/mL) or cIg. Graphs showing the frequencies of TNFα-, IFNγ-, and CD107a-positive CD8+ T cells (n = 16 MM patients). (M) Graphs showing the concentrations of the indicated cytokines in the supernatants of purified MM patient BM CD8+ T cells stimulated by anti-CD3/CD28/CD2 microbeads for 24 hours in the presence of anti-TIGIT mAbs (10 μg/mL) or cIg (n = 11 patients with MM). (A,D-H) Data are presented as mean ± SEM, with each symbol representing an individual mouse. Statistical differences between multiple group were determined by 1-way ANOVA (D-F) with Tukey posttest analysis; differences between 2 groups were assessed using a (A) Mann-Whitney U, 2-way ANOVA (G-H), or (L-M) Wilcoxon matched-pairs signed rank test; (B-C,I-K) Differences in survival were determined by log-rank sum test. *P < .05; **P < .01, ***P < .001, ****P < .0001. cIg, control immunoglobulin; IP, intraperitoneal.

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