Fig. 3

Histology and macrophage infiltration in Renca-MUC1 tumors treated with radiation and vaccine. Established Renca-MUC1 tumors were treated with 8 Gy radiation (Rad) and MVA-MUC1-IL-2 vector (Vaccine) administered peritumorally at 10⁷ PFU using either Schedule 1 of radiation followed by two vaccine treatments (Rad + Vaccine) or Schedule 2 of vaccine followed by radiation and a second vaccine treatment (Vaccine + Rad) as described in Fig. 2. Tumors sections, obtained at one week after the last vaccine treatment, were stained for H&E or by IHC for F4/80⁺ macrophages. The main findings were labeled with T for tumor, V for vessels, N for necrosis, M for mitosis, G for giant cells, H for hemorrhages and IF for inflammatory cells. In H&E stained tumor sections, control tumors presented as sheets of pleomorphic epithelial cells with frequent mitosis and minimal immune cells infiltrates. Radiation-treated tumors showed areas of necrosis, numerous giant cells with abnormal mitosis, eccentric nuclei or large vacuoles. Focal infiltration of immune cells was seen. Tumors treated with radiation and vaccine showed extensive tumor destruction with large areas of necrosis and hemorrhages, a few remaining giant tumor cells and overall decreased cellularity. Staining for F4/80⁺ macrophages showed few macrophages within control and radiation treated tumors but a heavy infiltration of macrophages in radiation and vaccine treated tumors (arrows). The extent of tumor destruction and immune infiltration was greater with Vaccine + Rad sequence than with Rad + vaccine sequence. All magnifications X40