Establishment and characterization of a subacute sclerosing panencephalitis (measles) virus persistent infection in BGM cells.

Infection of BGM cells with the Halle isolate of subacute sclerosing panencephalitis (SSPE) gave rise to a persistent infection (BGM/Halle), whereas infection of another African green monkey kidney cell line (Vero) under identical conditions led to a lytic infection. The BGM/Halle cells multiplied more slowly than the non-infected cells (even when the medium was changed daily). Under such conditions 10(7) to 10(8) p.f.u./ml/24 h of measles virus was released into the medium. It was established that the persistent infection was not due to the accumulation of thermosensitive mutants and that the virus was not modified as measured by several biological parameters. The virus released from BGM/Halle cells had, however, acquired an ability to give rise to a persistent infection in Vero cells. The quantity of virus released from persistently infected Vero cells was very low (10(2) to 10(3) p.f.u./ml). It was concluded that a host-cell factor plays a role in the restriction of virus replication.