The effect of irradiation on demyelination induced by avirulent Semliki Forest virus

A dose of 500 rad total body irradiation before Semliki Forest virus infection was the most effective in producing multiple foci of demyelination in Swiss mice. Animals receiving this dose had the highest virus titre of Semliki Forest virus persisting in the brain and a delayed antibody response. In spite of extensive demyelination no obvious clinical signs such as paralysis were observed.