Attenuated vaccinia viruses (VV) selectively replicate in malignant cells and confer oncolytic effect in vivo.
Here we demonstrate that oncolytic VV may also be used as a diagnostic agent for tumor-bearing mice. A series of recombinant
vaccinia viruses has been constructed expressing optical reporters to mediate emission of bioluminescent and
fluorescent light which can be visualized. Data show that following systemic virus delivery the developing tumors can be
non-invasively visualized in mice in vivo. Renilla luciferase and Aquoria GFP have been effective in imaging xenografted
PC-3 prostate and orthotopic MB-49 bladder tumors. Brighter reporters, Gaussia luciferase and Renilla GFP have been
used for imaging TRAMP prostate cancer and C6 subcutaneous model of glioma. The C6 imaging data have been
corroborated by traditional MRI. We are also developing a VV-mediated system for tumor detection in far red or near
infra red fluorescent light. Results suggest that VV-mediated imaging is a promising alternative for early diagnosis of
various human cancers.