Analysis of explanted C1498 tumors revealed robust VSV infection of tumors. C1498 tumors from mice treated IV with 108 TCID50 VSV-mIFNβ-NIS, with and without anti-PD-L1 Ab, were excised on day 3 after VSV therapy. (A) (i) Representative images of immunohistochemical staining for distribution of VSV infectious foci and CD8 T cells in tumors. (ii) The extent of VSV and CD8 staining in tumors (percentage of coverage) was analyzed on NIH ImageJ software. Data represent mean ± SEM (n = 3 mice) from each group. (B) Viral titers recovered from explanted tumors of mice that received 108 TCID50 VSV. The data are expressed as TCID50 virus per mg of tumor (n = 3, mean ± SEM). (C) (i) Immunohistochemical staining showing PD-L1 expression on C1498 tumors, harvested at 3 days post-Ab. Scale bar represents 100 μm. (ii) Histogram and error bars represent the mean ± SEM (n = 3 mice) from each group. tx, treatment.
