Article thumbnail

Stable Integration Vector for Nutrient Broth-Based Selection of Attenuated Listeria monocytogenes Strains with Recombinant Antigen Expression▿

By Laurel L. Lenz, William A. Huang, Chenghui Zhou, Zhongxia Li and Richard Calendar

Abstract

Recombinant Listeria monocytogenes strains induce strong cellular immune responses and may prove useful for antigen delivery for the vaccination of humans. However, the genetic systems currently available for the stable expression of recombinant antigens by L. monocytogenes rely on the use of antibiotic resistance genes. We report on a derivative, pPL2dalGlnA, of the Listeria monocytogenes pPL2 integration vector that completely lacks drug resistance genes. The selectable markers in pPL2dalGlnA are glutamine synthetase (GlnA) and alanine racemase (Dal). This novel vector was stably maintained in auxotropic L. monocytogenes strains that normally require d-alanine. The pPL2dalGlnA vector also partially restored the ability of an L. monocytogenes Δdal Δdat strain to colonize the spleens and livers of infected mice. A novel, highly attenuated strain of L. monocytogenes with quadruple deletions was also engineered by deleting the L. monocytogenes actA and plcB virulence genes from a Δdal Δdat strain. Infection of mice with recombinants of this mutant strain that express the antigen from pPL2dalGlnA were shown to elicit CD8+ T-cell responses to human immunodeficiency virus Tat. This vector system is thus useful for stable antigen expression and vaccination studies

Topics: Vaccine Research
Publisher: American Society for Microbiology (ASM)
OAI identifier: oai:pubmedcentral.nih.gov:2546660
Provided by: PubMed Central
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://www.pubmedcentral.nih.g... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.