Efficacy and stability of a subunit vaccine based on glycoprotein E2 of classical swine fever virus

The purpose of this study was to determine the efficacy and stability of an E2 subunit vaccine against classical swine fever virus (CSFV). The vaccine , which contains E2 produced in insect cells by a baculovirus expression ve ctor is a potential marker vaccine, as it allows discrimination between inf ected and vaccinated pigs. Several vaccination-challenge experiments were p erformed to determine the dose that protects 95% of the vaccinated pigs (PD 95), and to determine the stability and efficacy of the vaccine several mon ths after production. A single vaccination with a vaccine dose of 32 mu g E 2 - the estimated PD95 - in a water-oil-water adjuvant prevented clinical s igns and mortality due to a CSFV challenge-inoculation three weeks after va ccination Moreover, virus transmission to susceptible sentinel pigs was pre vented in nearly all groups of pigs vaccinated with this dose. The vaccine was stable for at least 18 months, and retained its full potency. These fin dings indicate that the E2 marker vaccine merits further evaluation for sui tability for use in a control program during an outbreak of CSF. (C) 1999 E lsevier Science B.V. All rights reserved.