Production of Borna Virus in Tissue Culture

Abstract

This is the first report on the cultivation of Borna virus in tissue culture. In subcultures of lamb kidneys, the virus reproduces with a latent period of several weeks. At 48–72 hr postinfection, the infectivity of the subcultures for rabbits disappears but recurs after 5–10 weeks. The infectivity is not lost by subcultivation of the cells, and the infected cultures show an enhanced growth rate. After several weeks, plaque-like areas with enlarged cells and nuclei can be observed in the infected cultures. Nuclear inclusion bodies are found, but very rarely, and show no correlation to the infectivity of the cells for rabbits. The behavior of Borna virus in cell cultures is typical of a slow virus infection, and thus, the Borna infection of tissue cultures offers itself as a new model for the study of slow viruses.