1887

Abstract

Summary

Twenty-eight mutations, representing mutation in five different polypeptide-coding regions of the foot-and-mouth disease genome, were examined for their effect on the virulence of the virus for suckling mice. Five types of mutation were examined: temperature-sensitive (), electrophoretic (), co-variant temperature-sensitive and electrophoretic (), guanidine-resistant ( ) and putative co-variant guanidine-resistant and electrophoretic ( /). All the mutations and three out of the 11 non- mutations produced some reductions in virulence. In the majority of cases this reduction in virulence was shown to co-vary with the mutation. No correlation was observed between the site of a mutation or its ‘cut-off’ temperature and the extent of the reduction in virulence.

Studies of the growth of a small selection of mutants suggested that for most mutants their reduced virulence was a trivial effect of their slow growth rate. With one exception they all eventually grew to parental virus levels, the resulting virus being temperature-sensitive and the disease indistinguishable from that caused by the parental virus. The one exception was an avirulent mutant which only grew to one-thousandth the titre of the parent virus. This mutant did not cause disease and was therefore considered to be the only avirulent mutant. Its mutation was in the coat protein-coding region of the genome, probably the region coding for VP3.

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/content/journal/jgv/10.1099/0022-1317-54-2-263
1981-06-01
2019-10-17
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http://instance.metastore.ingenta.com/content/journal/jgv/10.1099/0022-1317-54-2-263
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