Effects of IL-15 on infection of PBMC by HSV-1. PBMC from 3 healthy blood donors were infected with HSV-1 and cultured in the absence or presence of 25 to 50 ng/mL. On day 4 PI, cells were analyzed by standard immunofluorescence with anti–HSV-1 MoAb. The percentage of infected cells was calculated after counting a minimum of 500 cells. *P < .05.