Pathogenicity and immunogenicity of a vaccine strain of Listeria monocytogenes that relies on a suicide plasmid to supply an essential gene product.

ABSTRACT: Listeria monocytogenes is a bacterial pathogen that elicits a strong cellular immune response and thus has potential use as a vaccine vector. An attenuated strain, L. monocytogenes dal dat, produced by deletion of two genes (dal and dat) used for d-alanine synthesis, induces cytotoxic T lymphocytes and protective immunity in mice following infection in the presence of d-alanine. In order to obviate the dependence of L. monocytogenes dal dat on supplemental d-alanine yet retain its attenuation and immunogenicity, we explored mechanisms to allow transient endogenous synthesis of the amino acid. Here, we report on a derivative strain, L. monocytogenes dal dat/pRRR, that expresses a dal gene and synthesizes d-alanine under highly selective conditions. We constructed the suicide plasmid pRRR ca

SUBMITTER: Zhao X 

PROVIDER: S-EPMC1231070 | biostudies-literature | 2005 Sep

REPOSITORIES: biostudies-literature