Figure 4. IL4 blockade slows tumor regrowth following RT in a CD8⁺ T cell-dependent manner.

A–B) Surface expression of IL4Rα (A) and IL13Rα1 (B) as measured by mean fluorescence intensity (MFI) minus background in cells isolated from MMTV-PyMT mammary tumors as indicated, and as compared to equivalent populations in the spleens of non-tumor-bearing animals (lower graphs). Data are displayed as mean ± SEM with n=3 mice per group. Statistical significance determined by an unpaired t-test compared to the spleen. MØ, macrophage; mono, monocyte; DC, dendritic cell. C–D) Orthotopic PyMT-derived tumors were grown to a median diameter of 1.0 cm and then the tumor-bearing mice were enrolled in the study. On Day 1 mice were treated with localized gamma irradiation (5 Gy) and total tumor burden/animal assessed every 3 days until endpoint. αIL4 neutralizing antibody and/or αCD8-depleting antibody were administered 2 days prior to RT and then every 5 days for the duration of the experiment. Treatment schematic is depicted at top and data are displayed as mean tumor burden ± SEM (>5 mice/group). Statistical significance was determined by two-way ANOVA. E) Number of CD3⁺CD4⁺, CD3⁺CD8⁺, and CD11b⁺F4/80⁺ cells within tumors 2 days following treatment with RT. Data are depicted as mean number of cells ± SEM as a % of CD45⁺ cells as analyzed by flow cytometry (>5 mice/group). F) Orthotopic PyMT-derived tumors were grown to a median diameter of 1.0 cm and tumor-bearing mice were administered intravenous paclitaxel (PTX; 10 mg/kg) and total tumor burden/animal assessed until endpoint. αIL4 neutralizing antibody was administered 1 day prior to CTX and then every 5 days for the duration of the study. Treatment schematic is depicted at top and data are displayed as mean tumor burden ± SEM (>5 mice/group). Statistical significance was determined by two-way ANOVA. G) Orthotopic PyMT-derived tumors were implanted into syngeneic ILR4α-proficient (+/−) and –deficient (−/−) mice and grown to a median diameter of 1.0 cm. Mice were then treated with intravenous paclitaxel (PTX; 10 mg/kg) and total tumor burden/animal assessed until endpoint. αCD8-depleting antibody was administered 1 day prior to CTX and then every 5 days for the duration of the study. Treatment schematic is depicted at top and data are displayed as mean tumor burden ± SEM (>5 mice/group). Statistical significance was determined by two-way ANOVA. (H) MMTV-PyMT transgenic mice were treated with αIL4 and/or αIL13 mAbs between 80 to 85 days of age, and 5 days later were treated with 10 mg/kg PTX as indicated. Tumor volume is shown as a relative change between the first dose of PTX and 15 days later. Treatment schematic is depicted at top and data are displayed as the mean ± SEM (>6 mice/group). For all figures statistical significance is shown as *p < 0.05, **p < 0.01, ***p < 0.001.