CHARACTERIZATION OF AN AROMATIC AMINO ACID-DEPENDENT LISTERIA-MONOCYTOGENES MUTANT - ATTENUATION, PERSISTENCE, AND ABILITY TO INDUCE PROTECTIVE IMMUNITY IN MICE

A transposon insertion mutant of Listeria monocytogenes was shown to b e deficient in prephenate dehydratase, an enzyme acting late in the pa thway for biosynthesis of phenylalanine. This mutant had reduced virul ence in mice. The mutant and parent strains persisted to the same exte nt in the tissues of infected mice and elicited similar degrees of spl enomegaly. Mice vaccinated with the mutant were protected significantl y from subsequent challenge with virulent L. monocytogenes.