Differential gene expression in implanted CT26 tumors treated with mVG161 compared to equivalent tumors injected with VG160 (Figure S5) revealed that infection with mVG161 bearing IL-12, IL-15, and IL-15RA transgenes powerfully stimulates a prototypical Th1 immune response (e.g., IFN-γ, TNF, and IL18). Here, IL15 is linked to infection.