Immune reconstitution prevents continuous equine infectious anemia virus replication in an Arabian foal with severe combined immunodeficiency: Lessons for control of lentiviruses

Acute infection with equine infectious anemia virus (EIAV), a lentivirus of horses, results in a persistent high-level viremia in Arabian foals affect ed with severe combined immunodeficiency (SCID). This observation argues ag ainst the idea that the transient nature of acute lentiviral viremia is sol ely a function of viral population dynamics. To extend these studies, EIAV- specific immune reconstitution was attempted prior to EIAV challenge in two SCID foals, using adoptively transferred virus-stimulated lymphocytes deri ved from persistently EIAV-infected half sibling donors. Following transfer , lymphocyte engraftment occurred in one foal, and EIAV-specific cytotoxic T lymphocytes as well as neutralizing antibody activity developed. Followin g a brief period of plasma viremia in this foal, EIAV replication was contr olled and plasma virus could not be detected by RT-PCR or culture. These re sults provide further direct evidence that a specific immune response is re quired for termination of plasma viremia in acute lentiviral infections. (C ) 2001 Academic Press.