Oncolytic virotherapy as immunotherapy

Description Recognizing immune responses to oncolytic virotherapy opens the way for new combinations Oncolytic virus (OV) therapy is now something of a misnomer. The initial paradigm was that naturally occurring or genetically engineered viruses would preferentially infect, replicate in, and lyse cancer cells relative to normal cells, leading to selective direct cytotoxicity. The immune system used to be considered detrimental, given its potential to recognize and respond to the virus, prevent its replication, and limit viral spread and tumor cell killing (1). This view has now been largely replaced by a model in which infection of the tumor by the virus makes it more visible to the immune system for recognition and attack. Tumor cell killing by the virus and/or immune effector cells effectively generates an in situ vaccine, with tumor antigens released into a microenvironment modified by viral infection to reverse tumor-induced immune suppression.