CD274 and neoplasm: We also demonstrate that scFv PD-L1 effectively block PD-1/PD-L1 interaction leading to alleviation of PD-1/PD-L1 mediated immune suppression in a co-culture system in vitro. This activity was further supported by data from multiple syngeneic mouse models showing that tumors infected with RRV-scFv-PDL1 conferred robust and durable immune-mediated anti-tumor activity comparable or superior to systemically administered anti-PD1 and anti-PD-L1 monoclonal antibodies.