C57BL/6 mice were inoculated with 2 × 10⁵ TC-1 tumor cells subcutaneously. Eight days later, mice were treated with Alb-Flt3L followed by cisplatin 24 hours later. The treatment regimen consisting of Alb-Flt3L followed by cisplatin was performed every 5 days for a total of 3 times. (A) Tumor growth and (B) survival curves of TC-1 tumor–bearing mice treated with the indicated reagents (n = 5). For the assessment of tumor control in large tumors, C57BL/6 mice were inoculated with 2 × 10⁵ TC-1 tumor cells subcutaneously (n = 5). Tumors were allowed to grow until they reached more than 300 mm³, which was approximately 21 days. Mice were then treated with 100 μg of Alb-Flt3L or 20 μg of Flt3L (equimolar amounts); cisplatin was administered 24 hours later. This regimen was administered approximately every 3 to 4 days for a total of 3 cycles. Alb-Flt3L or Flt3L treatment continued every approximately 3 days. (C) Tumor growth curves for TC-1 large tumor experiment. WT C57BL/6 mice were inoculated with 2 × 10⁵ TC-1 tumor cells (n = 5). Twenty days later, the mice were treated with Alb-Flt3L, Flt3L, cisplatin, cisplatin + Flt3L, cisplatin + Alb-Flt3L, or vehicle (control). (D) Tumor growth curves following treatment of WT or Batf3^–/– mice with Alb-Flt3L + cisplatin (n = 5). PBMCs were collected from mice 20 days after initiation of treatment and prepared for flow cytometry. Percentages of (E) CD4⁺Ki-67⁺, (F) CD8⁺Ki-67⁺, (G) CD4⁺IFN-γ⁺, and (H) CD8⁺IFN-γ⁺ cells in WT or Batf3^–/– mice treated with Alb-Flt3L + cisplatin (n = 5). Data shown are the percentage of parental cells (CD4⁺ or CD8⁺ T cells) (n = 5). TC-1–bearing WT C57BL/6 mice were administered blocking or depleting antibodies as indicated and treated with Alb-Flt3L + cisplatin and (I) tumor growth was determined (n = 5). (J) Similar to I, but in Batf3^–/– mice (n = 5). TC-1 tumor–bearing mice were treated with 4 doses of anti–PD-L1 every 3 days starting on day 5. In addition, Alb-Flt3L was administered every 3 days starting on day 5. Cisplatin was administered on days 21 and 28 after tumor inoculation. (K) Tumor growth and (L) survival curves for the indicated treatment groups (n = 9). PBMCs were collected 30 days following tumor inoculation and prepared for flow cytometry. Frequency of (M) CD4⁺Ki-67⁺, (N) CD8⁺Ki-67⁺, (O) CD4⁺IFN-γ⁺, (P) CD8⁺IFN-γ⁺, (Q) CD4⁺TNF-α⁺, and (R) CD8⁺TNF-α⁺ cells among PBMCs in the indicated treatment groups. Data shown are the percentages of parental cells (CD4⁺ or CD8⁺ T cells) (n = 9). **P < 0.01; ***P < 0.001; ****P < 0.0001 by 1-way ANOVA (bar graphs) or 2-way ANOVA (tumor growth curves), except tumor survival curves in B and L, which were assessed using the log-rank test, and 2-group comparisons, which used the 2-tailed Student’s t test (E–H).