[Multiploid virions of the Venezuelan equine encephalomyelitis virus. Isolation and properties].

Multiploid virions present in the population of multiploid-forming mutant of Venezuelan equine encephalomyelitis (VEE) virus were isolated from preparations of purified and concentrated virus by methods of zonal centrifugation in glycerin density gradient or gel filtration through biogel A-150 m. The portion of multiploid particles in such preparations reached 70%-90%. The isolated multiploid virions retained their morphology, infectivity and hemagglutinating activity. The multiploid particles were found to differ from standard virions in the sedimentation rate and buoyant density.