Isolation and characterization of a 14500 molecular weight protein from brains and tissue cultures persistently infected with borna disease virus.

A protein with an apparent molecular weight of 14500 (14.5K) was extractable from homogenates of Borna disease virus-infected brains and tissue cultures using high concentrations of detergent and salt and by differential centrifugation procedures. The protein, present in an aggregated form, was remarkably resistant to proteinase K. Specific antibodies prepared in the homologous system (rat) recognized the 14.5K protein from various sources (infected brain of rat, mouse or chicken, and tissue cultures), but did not neutralize infectivity nor stain Borna disease virus-specific antigens from in vitro or in vivo preparations. Post-infection immune sera from different animal species did not detect the protein. This 14.5K protein was infection-specific but not disease-specific, and is inferred to be part of an internal virion component.