Figure 7. Batf3-driven dendritic cells are sufficient and required for recruitment of effector T cells into the TME.

(A) CD11c-DTR/WT (grey circles) and CD11c-DTR/Batf3^−/− (black circles) bone marrow chimeras were generated and 21 days following tumor induction diphtheria toxin was given to deplete DTR expression DC. Day 27 post-tumor induction, 1×10⁶ effector T cells were transferred and their accumulation in the tumor was assessed 48h later. Shown are number of 2C T cells detected in the tumor (n = 4). The tumor weight at time of analysis was 0.8 g ± 0.1 g for WT chimeras and 0.6 g ± 0.1 g for Batf3^−/− chimeras (mean ± SD). (B–E) BP-SIY and BPC-SIY tumor-bearing mice were injected twice intra-tumorally with Flt3-ligand-derived DC or control injected with PBS 72 hr prior to intravenous injection of effector 2C T cells. 3 days post-T cell injection, the percent (B) and absolute number (C) of 2C T cells and overall T cells (D) in the tumor and the percentage of 2C T cell within CD8⁺ T cells in the TdLN (E) were assessed and are depicted as number per gram of tumor or percent in CD8⁺ T cells n = 4, 4, 3 or 6 mice per group (from left to right); data are pooled from two independent experiments). The tumor weight at time of analysis across all experiments was 1.3 g ± 0.1 g for BP-SIY + 2C, 1.7 g ± 0.22 g for BPC-SIY + 2C, 1.5 g ± 0.1 g for BPC-SIY + DC and 1.4 g ± 0.18 g for BPC-SIY + DC + 2C (mean ± SD). Box plots show median with 95^th percentile, maximal deviation shown by error bars; significance was assumed with p ≤ 0.05, with * ≤ 0.05; ** ≤ 0.01. See also Figure S5.