Figure 4

Winn Assays to assess the in vivo activity of anti-tumor CD8⁺T cells from animals treated with IgG2a (control) or sTGF-βR. Tumor volume was calculated by the formula (π*long axis*short axis*short axis)/6 and displayed as mean volume (mm³). Error bars represent standard error of the mean (SEM). CD8⁺ T cells were isolated from the spleens of non tumor-bearing animals, tumor-bearing animals treated with IgG2a, or tumor-bearing animals treated with sTGF-βR. These CD8⁺ T cells were then mixed with fresh AB12 tumor cells according to a ratio of 3 CD8⁺ T cells to 1 AB12 tumor cell. These mixtures were then injected into the flanks of naïve BALB/c mice (n=5 per group). Tumors were then allowed to grow for 1 week. Tumors from mixtures of AB12 tumor cells and CD8⁺ T cells from non tumor-bearing animals grew to an average size of approximately 100 mm³ (“naïve” group). Tumors from mixtures of AB12 tumor cells and CD8⁺ T cells from animals treated with IgG2a grew to an average size of approximately 30 mm³ (“control” group), representing a 68% inhibition of growth (* = p < 0.01). However, tumors from mixtures of AB12 cells and CD8⁺ T cells from animals treated with sTGF-βR (“TGF-β-blockade” group) grew to a significantly larger average size than the control group (** = p < 0.05) and to the same degree as the naïve group (NS = p > 0.05). Displayed values are mean volume (mm³). Error bars represent SEM.