Atypical dissemination of the highly neurotropic Borna disease virus during persistent infection in cyclosporine A-treated, immunosuppressed rats.

In adult rats infected with Borna disease virus, the virus was found exclusively in the brain, whereas in cyclosporine A-treated rats, infectious virus was also detected in peripheral nerve fibers and, unexpectedly, in adjacent organ-specific cells. In contrast to untreated virus-infected rats, no major histocompatibility complex class II expression was found in the brain of cyclosporine A-treated animals.