Abstract
The physiological defects associated with 17 temperature-sensitive mutants of the KENYA 3/57 strain of foot-and-mouth disease virus were examined in terms of the ability of the mutants to produce infective RNA and complement-fixing antigen under restrictive conditions. The yields of infective RNA obtained with different mutants ranged from less than 0.31 to 87% of normal, and of complement-fixing antigen from 12.6 to 99.6% of normal. Genetic recombination was observed in crosses of mutants with different physiological effects, such that the mutants could be arranged in five groups.
* Present address: M.R.C. Virology Unit, Institute of Virology, Church Street, Glasgow, W.1.