Figure 2.

Mechanisms of oncolytic virus effects on neoplastic cells.

Notes: Oncolysis due to viral infection and immune stimulation are thought to occur simultaneously within the tumor microenvironment. Elimination of cancer cells occurs by direct infection of the tumor cell, virus replication, and subsequent cell lysis. An infiltrate of cytotoxic T lymphocytes and natural killer cells is often detected. These innate immune cells are able to lyse infected tumor cells through release of granzymes and perforins. Chemotaxis of neutrophils and macrophages to the site of virus infection is often seen and is likely due to the presence of cellular debris and chemokine release from infected and lysed cancer cells and/or healthy cells surrounding the tumor. Presentation of viral and tumor antigens by macrophages can lead to activation of helper T-cells and production of antiviral and antitumor antibodies by B lymphocytes. Ideally, this leads to elimination of the tumor.