Fig. 2.

Combining oncolytic vectors and checkpoint inhibitors. A Illustration of the PD-1/PD-L1 axis between a T cell and cancer cell, which suppresses T cell activation. B Oncolytic viruses have the ability to directly lyse and kill cancer cells (grey cells), but also can exert a change in the local tumor microenvironment by increasing immune cell activation and PD-L1 expression on cancer cells. C Following priming by an oncolytic virus infection and transition to a ‘hot’ tumor microenvironment, checkpoint inhibitors (anti-PD-1 antibody) are more efficacious at decreasing T cell suppression