Doctors have long observed that certain viruses can slow the progression of cancer. Oncolytic immunotherapy aims to build on this potential by using genetically modified viruses to target tumors in two important and complementary ways.
By deleting certain viral genes, scientists can make viruses that can replicate effectively in tumor cells but not in normal cells. Tumor-selective viral replication can cause tumor cells to lyse, or burst open (oncolysis). The virus can also be modified to produce human signaling proteins that summon immune cells to the site of the lysed tumors, where they encounter tumor antigens. The aim is to generate a broad immunotherapeutic response that can help cytotoxic T cells to recognize and attack distant tumor metastases in the body.