CONDITIONAL LETHAL MUTANTS OF RABBITPOX VIRUS .3. TEMPERATURE-SENSITIVE (TS) MUTANTS - PHYSIOLOGICAL PROPERTIES COMPLEMENTATION AND RECOMBINATION

Temperature-sensitive (ts) mutants can be readily obtained from rabbitpox virus grown in the presence of bromodeoxyuridine. Eighteen mutants were selected for study; all gave a plaque count at the restrictive temperature (39.5°) which was <10-5 the plaque count at the permissive temperature (34.5°). A number of physiological properties of these mutants were examined. All mutants except one produced u+ pocks on the chorioallantoic membrane. All the ts showed the same inactivation kinetics as wild-type rabbitpox virus, all synthesized DNA at the restrictive temperature and all except three produced the same range of soluble antigens at the restrictive temperature as they produced at the permissive temperature. Mixed infection experiments showed that most mutants complemented each other and all recombined with each other. © 1968.