UV-HSV-1 synergizes with IL-15 in activating PBMCs to induce cytolysis of leukemic cells. (A) Isobologram analysis of the interaction of UV-HSV-1 and IL-15 in stimulating PBMC-induced cytolysis of OCI-AML3 (30:1 effector:target). A fixed dose increase (5:1; UV-HSV-1:IL15) was used. *P < .05 from UV-HSV-1 or IL-15 alone. (B) Representative flow cytometry plots of an isobologram analysis of the interaction of UV-HSV-1 and IL-15 in stimulating expression of CD69 in NK cells (5:1 fixed dose increase). (C-E) Isobologram analysis of the interaction of UV-HSV-1 and IL-15 in stimulating degranulation and expression of IFN-γ in NK cells (5:1 fixed dose increase). *P < .01 from UV-HSV-1 or IL-15 alone.