TABLE 1.

Particle, PFU, and ICP4 FFU titers of typical stocks of HSV-1 strain 17 and dl1403 on different cell typesa

VirusParticlesVero cellsU2OS cellsHFFF cells
FFUPFUFFUPFUFFUHFFF PFU
Strain 171.0 × 10104.8 × 1082.0 × 1085.4 × 1089.1 × 1074.8 × 1074.8 × 107
dl14032.9 × 1092.6 × 1086.2 × 1062.3 × 1089.2 × 1079.3 × 1061.1 × 105
  • a All values are in units per milliliter. ICP4 FFU titers were determined 6 h after infection. Repeat determinations showed that the experimental variation was less than twofold for PFU and FFU determinations but up to fivefold for particle determinations.