Impact of process conditions on the centrifugal recovery of a disabled herpes simplex virus

Despite continuous improvements in culturing and recovery techniques, high-titer stocks of purified disabled herpes simplex virus type-1 (HSV-1 DIS) vector for drug discovery and use in preclinical and clinical trials are currently difficult to achieve. Efforts to improve their centrifugal recovery have been addressed in this paper. The operation of a swing-out centrifuge rotor was assessed, and its operational conditions were defined for the recovery of viable HSV-1 DIS. 80% virus recovery was achieved after 90 min at 26000g. The 20% loss of virus was attributed to damage to the viral envelope by overcompaction of the pellet and impaction with the base of the centrifuge tube. Virus recovery was increased by a further 10% by using a fixed-angle centrifuge rotor operating at 26000g. Plaque assays of recovered HSV-1 DIS gave values on the order of 10(6) pfu/mL, compared to values typically above 10(9) pfu/mL obtained for the replication-competent HSV-1 viron.