Figure 5

Mode of action of the oncolytic virus VSV-GP in patient-derived HNSCC slice cultures. (A–C) Whole mount staining using VSV-N antibody (red) on OV treated HNSCC slice cultures at 48 hpi. Samples were cultivated under air–liquid conditions. Virus spread could be monitored throughout the entire slice (A). Rounded cells were detected (higher magnification in (B) (1), arrows in (C) (2) adjacent to virus positive cell debris (C, (2), asterisks). Scale bars represent 200 µm. (D–F) Co-immunofluorescent stainings of VSV-N (green) and aCas3 (red) were performed on two different whole-mounted OV-treated slices 48 hpi. Maximal projections (xy, yz) showed the presence of active Caspase-3 in VSV-N+ve cells (higher magnification in F). Scale bars represent 50 µm. VSV-N+ve virus factories (G, VSV-N-green) were localized in the cytoplasm of thin sections derived from OV-treated HNSCC slice cultures. Scale bars represent 20 µm and 10 µm in the insert. (H,I) Virus (VSV-N-green) could be detected in the EpCAM+ve tumor cell compartment (EpCAM-red, H). Some VSV-N+ve cells co-localized with Vimentin (red) in the tumor stroma (I). DAPI (blue) was used as nuclear counterstain. Scale bars represent 20 µm.