FIG 3.

Gene switch-controlled immunization by recombinant HSV-GS3. Mice in four groups (n = 10 per group) were administered 500,000 PFU/mouse of HSV-GS3 on both rear feet. The first HSV-GS3 group received a 45°C/10-min heat treatment 3 h after inoculation in the systemic presence of ulipristal (50 μg/kg administered i.p. at the time of inoculation) [HSV-GS3 (activated)], the second group received only heat treatment [HSV-GS3 (heat only)], the third group was administered only ulipristal [HSV-GS3 (uli only)], and the fourth group was left untreated [HSV-GS3 (unactivated)]. A further group was mock immunized with saline. At 21 days, the animals in the HSV-GS3 groups were boosted with another 500,000-PFU/mouse dose of HSV-GS3, and 10 days later, all the mice were challenged with a 20-fold lethal dose of wild-type HSV-1 strain 17syn+ applied to both rear feet. The data are presented as percent survival for each treatment group. ***, P ≤ 0.05. See Materials and Methods for further details. Comparable data were obtained from a second experiment (not shown), in which mice were immunized with 50,000 PFU/mouse of HSV-GS3 and were not boosted.