Evidence for a mouse pathogenicity locus in certain temperature-sensitive mutants of foot-and-mouth disease virus

Abstract

Serial tissue culture passaging of three foot-and-mouth disease temperature-sensitive mutants demonstrated the stability of their temperature sensitivity and mouse avirulence characteristics. Recovery of mouse-virulent temperature-sensitive viruses after passage of the mutants in mice suggested that these were not covariant expressions of the same locus, but were under the control of different genes.

Virulence of temperature-sensitive mutants of Sindbis virus in neonatal mice

“…Some measles virus ts mutants are capable of inducing hydrocephalus, unlike the encephalitis induced by the wild-type virus and some other ts mutants (7). For foot-and-mouth disease virus ts mutants, reduced manifestation of the disease in steers has been shown to be correlated with reduced virulence for mice (11). Several ts mutants of dengue virus have reduced virulence in mice, and in two cases this was associated with inability to produce viremia in monkeys (14).…”

“…For Sindbis virus, most ts mutants were less virulent for embryonated eggs than the wild type; some pathological features were apparent after infection with ts mutants that were not seen with the wild type (12). In general, the virulence of the ts mutants varied greatly in comparison to the wild-type; in some cases it has been postulated that virulence is determined by the genotype of the virus (7), by reversion and leak (12)(13)(14), or by a locus independent of the ts locus (10,11).…”