Novel strains of Salmonella typhimurium as potential vectors for gene delivery

DNA vaccines are known to induce long-term antigen specific cellular responses. We tested two new strains of Salmonella typhimurium, one carrying a mutation in a SPI-2 gene and the aroC-gene and another carrying mutations in the sifA- and aroC-genes, as potential DNA vaccine delivery vehicles. We compared them with the SL7207 strain and found that the new strains were more invasive, and that they were efficient mediators of gene transfer in vitro using EGFP as reporter gene. We tested the ability of the new strains to survive within the spleen, liver and mesenteric lymph nodes and evaluated their safety in C57/BL/6J mice.