BORDER DISEASE VIRUS - DELINEATION BY MONOCLONAL-ANTIBODIES

Many ovine pestiviruses from Britain and a number of atypical porcine isolates are largely unrecognised by monoclonal antibodies (mAbs) spec ific for reference strains of classical swine fever virus and bovine v iral diarrhoea virus (BVDV). Additional mAbs have therefore been produ ced using some of these ''unreactive'' pestiviruses. Two of the viruse s used were atypical porcine isolates (strains 87/6 and Vosges), whils t another had been isolated from a sheep (59386). Thirty-three mAbs we re selected, none of which recognised two reference strains of BVDV, b ut three of which recognised the Alfort strain of classical swine feve r. On the basis of radioimmunoprecipitation they were considered to be directed at one of three different pestivirus proteins (gp 53, gp 48 or p 125). Three virus subgroups were evident when the mAbs were used to type 16 ovine and two atypical porcine pestiviruses. One subgroup c ontained the Vosges and 59386 viruses and four ovine field isolates. T he second subgroup comprised the 87/6 virus, the Moredun and Aveyron r eference strains of border disease virus and four further ovine field isolates. Three of four ovine viruses making up the third subgroup had been previously categorised as BVDV-like and were largely unrecognise d by the new mAbs. The findings were in agreement with previous attemp ts to segregate some of the same viruses using partial genomic compari sons or cross-neutralization tests.