HSV-1 potently stimulates PBMC to kill leukemic cells. (A) Percent dead OCI-AML3 cells determined by flow cytometry as described in “Materials and methods” after culture with PBMCs or PBMCs pre-exposed for 16 hours to 0.1 pfu/PBMC HSV-1 (30:1 effector:target). *P < .05 from control; **P < .0001 from PBMCs alone. (B) Representative flow cytometry plots of OCI-AML3 cells infected or not with HSV-1, ±PBMCs or PBMCs pre-exposed to HSV-1. (C) Representative flow cytometry plots of OCI-AML3 cells exposed to live or UV-inactivated HSV-1. (D) Percent dead CD34⁺ primary leukemic cells determined by flow cytometry as described in “Materials and methods” after culture with PBMCs or PBMCs pre-exposed for 16 hours to 0.1 pfu/PBMC of HSV-1 or UV-HSV-1 (30:1 effector:target). *P < .01 from control; **P < .001 from PBMCs alone. (E) PBMCs were exposed to increasing concentrations of UV-inactivated viruses for 16 hours. Cytolytic activity against OCI-AML3 cells was determined as in B. *P < .05 from PBMCs alone; **P < .05 from VSV, Reo, or Ad at 10 pfu/PBMC.