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A new plasmid vector for DNA delivery using lactococci.

Valeria Guimarães1, Sylvia Innocentin, Jean-Marc Chatel

  • 1Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (ICB-UFMG), Belo Horizonte - MG, Brasil. valeria.guimaraes@cea.fr

Genetic Vaccines and Therapy
|February 12, 2009
PubMed
Summary
This summary is machine-generated.

Researchers developed a novel plasmid, pValac, for bacterial DNA delivery into epithelial cells using Lactococcus lactis. This system successfully delivered functional DNA, showing promise for oral DNA vaccines.

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Area of Science:

  • Molecular Biology
  • Microbiology
  • Vaccinology

Background:

  • Food-grade lactococci offer a novel strategy for DNA delivery into epithelial cells, enabling live oral DNA vaccine development.
  • A new plasmid, pValac, was engineered for antigen delivery via lactococci, combining eukaryotic and prokaryotic DNA regions.
  • The pValac plasmid facilitates antigen cloning under a eukaryotic promoter for host cell expression and bacterial replication/selection.

Purpose of the Study:

  • To construct and evaluate the functionality of the pValac plasmid for DNA delivery into epithelial cells.
  • To assess the capability of Lactococcus lactis strains carrying the pValac plasmid to deliver functional DNA.
  • To demonstrate the potential of pValac as a tool for developing live oral DNA vaccines.

Main Methods:

  • Construction of the pValac plasmid with eukaryotic and prokaryotic DNA components.
  • Cloning of the Green Fluorescent Protein (GFP) open reading frame into pValac (pValac:gfp) for functionality assessment.
  • Transfection of PK15 cells with pValac:gfp and invasiveness assays using Lactococcus lactis inlA+ strains in Caco-2 cells.

Main Results:

  • Transfection with pValac:gfp resulted in observable GFP expression in PK15 cells.
  • Lactococcus lactis inlA+ strains successfully invaded Caco-2 cells.
  • The invasive L. lactis strains delivered a functional expression cassette (pCMV:gfp) into epithelial cells.

Conclusions:

  • An invasive Lactococcus lactis strain harboring the pValac plasmid demonstrates potential for DNA delivery and subsequent gene expression in epithelial cells.
  • The pValac system shows promise for applications in genetic engineering and vaccine development.
  • Future research will focus on in vivo studies to evaluate DNA delivery in intestinal cells.