(A) Immunocompetent (BALB/c) mice bearing JC tumors were treated via a single tail vein injection with 1 × 108 PFU of vaccinia strains WR or WR-delB18R. Viral titer (PFU/g) in indicated tissues was determined by plaque assay after sacrifice of animals at indicated time points (n = 3 animals/time point).
(B) Immunohistochemistry staining for vaccinia coat proteins in tumor tissue sections of animals treated as above and sacrificed 24 h after viral treatment (magnification 40×).
(C) Survival of immunocompetent mice (C57/B6) bearing subcutaneous CMT-93 tumors and treated when tumors reached 50–100 mm3 with a single intratumoral (left) or intravenous (right) injection of WR-delB18R or PBS. Doses of 1 × 104 (circles), 1 × 106 (diamonds), or 1 × 108 (triangles) PFU of virus or PBS controls (squares) were used (n = 5 mice/group; p = 0.0047 for intravenous injections).