Fig. 4

Immunohistological characterization of GL261 tumor rejection in oHSV-1 treated mice. Representative histological sections of tumor tissues harvested from pre-treated (oHSV-1 treated: oHSV-1 and challenge) and un-treated mice (vehicle) mice, at 200x magnification. HE was followed by immunohistochemical staining with synaptophysin- and nestin-specific antibodies to better identify tumoral and non-tumoral tissue, respectively. Arrowheads in the panel showing nestin staining of oHSV-1 treated mice point to astrocytosis-enriched areas in both brain hemispheres. MHC-II expression was observed on myeloid cells concentrated over the tumor bed in both brain hemispheres of oHSV-1 treated mice (oHSV-1 treated) or dispersed along the GL261 tumor (vehicle). Ki67-positive cells are abundant in tumors isolated from non-treated mice (vehicle). HE, hematoxylin and eosin. Scale bar corresponds to 50 μM