Cultivation of Egg-Adapted Theiler's Mouse Encephalomyelitis (TO) Virus in Chick Tissue Culture

Abstract

An egg-adapted strain of Theiler''s mouse encephalomyelitis virus (TO) has been carried through 42 passages in vitro on embryonic chick tissue. Attempts to adapt the mouse passage virus directly to chick tissue culture were unsuccessful. Preliminary growth in embryonated eggs, followed by tests in mice of 20% embryo suspensions, facilitated the titration of tissue culture fluids. One of 3 strains of approx. the same mouse-infective titer failed to adapt either to egg or tissue culture.