Fig. 1. Mn is essential for immune responses against tumors.

a, b Wild-type (WT) Mn-insufficient (–Mn) and control (+Mn) mice were inoculated with the indicated numbers of B16F10 cells subcutaneously (n = 8). Tumorigenesis was monitored every other day for 90 days (a). Tumor volume above 50 mm³ was defined as tumorigenesis, tumor volume below 50 mm³ after 90 days was recorded as tumor-free (b). c, d Representative images of tumors (c), tumor sizes and tumor weights (d) in WT control (Con) and Mn-insufficient mice (–Mn) (n = 6 per group) after subcutaneous (s.c.) inoculation of 1 × 10⁵ B16F10 cells. e Representative FACS data of the frequency of tumor infiltrating CD8⁺ T cells of mice as in (c). f, g Quantification of tumor infiltrating CD8⁺ T cells (f) or CD4⁺ T cells (g) of the mice as in (a). h B16F10 tumors from (c) were stained with anti-CD8-FITC or anti-CD4-FITC and counterstained with DAPI. Scale bar, 50 μm. i, j Representative FACS data and quantification of tumor infiltrating IFNγ⁺CD8⁺ T cells (i) and TNFα⁺CD8⁺ T cells (j) of mice as in (c). k Representative images (left) and quantification of lung weights (right) in control (Con) and Mn-insufficient mice (–Mn) (n = 6 per group) at day 21 after intravenous (i.v.) injection of 1 × 10⁵ B16F10 cells. Data represent analyses of the indicated n mice per group, means ± SEM. Data are representative of three independent experiments. ***P < 0.001; ****P < 0.0001.