Diplomatic immunity: turning a foe into an ally.

Striking a balance between subversion of antiviral immune responses and enhancement of potentially therapeutic, antitumor cytotoxic responses is a challenge at the forefront of oncolytic virus (OV) research. Some of the immune hurdles that must be overcome to maximize OV delivery to spread throughout tumor beds, and an outline of some of the strategies developed to deal with these obstacles are reviewed. In addition, current research that may lead to antitumor immunity during, or subsequent to, OV therapy is discussed. Finally speculations are made upon emerging areas of viral and immune research that could be merged to create new therapeutic paradigms.