Table 1.

Approaches to enhancing the immunotherapeutic potential of oncolytic virotherapies, through either viral engineering or combination therapies

Modifications to the viral backbone	Viral virulence gene deletion	Vaccinia B18R (type I IFN-binding protein)
	Transgene expression (immune activating)	Cytokines (GM-CSF; type I IFN) TLR ligands (CpG expression) Tumor associated antigens (in situ vaccines) Bispecific T-cell engager
	Transgene expression (overcoming immunosuppression)	Chemokine receptors (CXCR4) Blockade of immune checkpoint inhibitors
Oncolytic virus combination with immunotherapy	Immune activating	Adoptive T-cell therapy (TCR, CAR T-cell etc) Vaccine therapy
	Overcoming immunosuppression	Blockade of immune checkpoint inhibitors