Isoelectric focusing of infectious particles of porcine pseudorabies virus strains in granulated dextran gels.

Isoelectric focusing of infectious particles of four strains of porcine pseudorabies viruses (Indiana, Iowa, Shope and an avirulent live-virus vaccine strains) are described. The pseudorabies virus strains exhibited great mobility in the electric field typical of viruses of the herpes group. Strains were considered electrophoretically homogeneous based on their respective isoelectric points. Maximal virus infectivity was concentrated in reproducible, stationary zones representing 73 to 86% of the total virus infectivity initially applied throughout the gels. All pseudorabies virus strains during processing and after isoelectric focusing retained their ability as whole complete particles to typically infect porcine kidney cell cultures. Virus from gel fractions produces foci in cell cultures that specifically reacted with pseudorabies virus fluorescent antibody conjugate. Prevention of foci could be demonstrated by neutralizing with pseudorabies virus monospecific antiserum. Maximal infectivity titers were demonstrated to be directly related to isoelectric points. Strain differences, in relation to virulence in swine, apparently is not related to isoelectric points.