BORNA-DISEASE VIRUS-SPECIFIC T-CELLS PROTECT AGAINST OR CAUSE IMMUNOPATHOLOGICAL BORNA-DISEASE

In this report we show that passive immunization of Lewis rats with vi able CD4(+), Borna disease virus (BDV)-specific T cells before infecti on with BDV resulted in protection against BD, whereas inoculation of these T cells after BDV infection induced clinical disease with more r apid onset than seen in BDV control animals. The protective as well as encephalitogenic effector functions of BDV-specific CD4(+) T cells we re mediated only by viable BDV-specific T cells. The protective situat ion was obtained by passive transfer of BDV-specific T cells into anim als inoculated later with virus, whereas the immunopathological situat ion was observed when virus-specific T cells developed normally or aft er adoptive transfer, and appeared on the scene after considerable vir us replication in the brain.