Following systemic intravenous delivery, REOLYSIN® binds peripheral blood mononuclear cells (PBMCs), mainly natural killer cells and dendritic cells. The binding of REOLYSIN to PBMCs protects the virus from antibody neutralization and helps deliver the virus to the primary tumor and metastatic sites. In addition, the binding of REOLYSIN to PBMCs also promotes immune cell activation, facilitating an anti-cancer immune response.