[Characteristics of defective rabies virus particles formed in chronically infected cultures].

Cultural fluids of BHK-21/13S and HEp-2 cells chronically infected with rabies virus were used to determine the structures sedimenting in the sucrose gradient of the slow infectious virus. These structures have a polypeptide composition similar to that of rabies virus and contain subgenome RNA. Morphologically they are spherical virions. After amplification in BHK-21/13S cells the structures protected mice from lethal doses of rabies virus. The results obtained allow designation of the structures as defective interfering particles of rabies virus. The evidence is given on their participation in the establishment and maintaining of the chronic infection.