Fig. 7. S100a4 deletion enhances phagocytosis in myeloid cells and increases T cell activation.

a A schematic summary of experimental design. S100a4 expressing GAMs (CD45^hiCD11b^hi) and CD4+ TILs (CD45⁺CD3⁺CD4⁺) were FACS sorted by GFP expression, and used in in vitro functional assays. b Fluorescence images showing phagocytosis of pHrodo^™ labeled (red) nanoparticles in FACS-sorted GFP⁺CD45^hiCD11b^hi GAMs from S100a4 heterozygous or homozygous hosts. An average number of particles/cell were calculated (n = 4 tumors each). P-value from two-tailed student t test. Error bars represent SEM. Scale bar: 50 µm. c Fluorescence images showing phagocytosis of pHrodo™ labeled (red) nanoparticles in FACS sorted CD45^hi CD11b^hi tumor-infiltrating GAMs from B6 or S100a4^−/− hosts. An average number of particles/cell were calculated (n = 3 tumors each). P-value from two-tailed student t test. Error bars represent SEM. Scale bar: 100 µm. d Box and whiskers plot showing IFN-γ levels measured by ELISA in FACS-sorted GFP+ CD45⁺CD3⁺CD4⁺ tumor-infiltrating T cells from S100a4 heterozygous or homozygous hosts. P-value represents two-tailed student’s t test (exact p-value = 1.8124E−12). Whiskers represent minimum and maximum values, the line inside the box represents the mean and the box extends from the 25th to 75th percentiles. n = 3 (heterozygous) and n = 5 (homozygous) gliomas, two experimental replicates from each tumor. e T cell proliferation assay using dye dilution. T cells were isolated from B6 spleens, labeled, and stimulated with CD3/Cd28 dynabeads then cocultured with FACS sorted GFP⁺CD45⁺CD3⁺CD4⁺ tumor-infiltrating T cells for 4-days. Dotted lines represent unstimulated T cells. P-value from two-tailed student t test. Whiskers represent minimum and maximum values, the line inside the box represents the mean and the box extends from the 25th to 75th percentiles. n = 3 (heterozygous) and n = 5 (homozygous) gliomas. Source data for b–e are provided as a Source Data file.