Figure 7
MHCII-positive immune cells, T-, B-, and NK cells did not significantly contribute to VACV-mediated tumor regression. GI-101A tumor-bearing mice were intraveneously (i.v.) injected with either 5 × 106 pfu/100 μl GLV-1h68 (a-e) or 1 × 106 pfu/100 μl GLV-1h68 (f-h) or PBS as a control. Immunosuppression was reached using 100/140 mg/kg cyclophosphamide monohydrate. (a) Fluorescence intensity measurement of recruited MHCII+ leukocytes in GLV-1h68 infected GI-101A tumors treated or untreated with CPA. The fluorescence signal was measured in 4 images of each tumor (n = 5). Shown are the mean values +/- standard deviations. (b) Tumor growth was monitored weekly by measuring the tumor volume of five mice in each group. Shown are the mean values +/- standard deviations. The study was repeated in an independent experiment. CPA treatment was started 10 days p.i. (arrow). (c-e) Distribution of GLV-1h68 within the tumor tissue 42 days p.i. was visualized by GFP in whole tumor cross-sections of 5 different tumors; the corresponding 8-bit grey-scale images of GFP and nuclei were used for calculation of the extent (%) of viral infection in tumor cross-sections using ImageJ software. Shown are the mean values +/- standard deviations. (d, e) Representative images of CPA-treated GLV-1h68-infected tumor (d) compared to untreated GLV-1h68-infected tumor (e) revealed a higher degree of oncolytic tissue destruction. (f-h) Tumor growth in athymic nude Foxn1 nu(f), B6.12956-Rag2 tm1FwaN12 (g), and Tac:NIHS-Lyst bg Foxn1 nu Btk xld(h) mice was monitored weekly by measuring the tumor volume of four to five mice in each group. In all models mice were intraveneously (i.v.) injected with 1 × 106 pfu/100 μl GLV-1h68 at day 39 post tumor cell implantation. Shown are the mean values + standard deviations. The asterisk (a, c) indicate a significant difference between experimental groups (* P < 0.05, *** P < 0.001; Student's t test). Scale bars represent 5 mm.