Use of Intracellular Bacteria for the Development of Tools for Tumor Therapy and the Detection of Novel Antibacterial Targets

Intracellularly replicating bacteria are suitable tools for a combined immunological and drug therapy of tumors. For example, virulence-attenuated strains of L. monocytogenes, Salmonella spp., Shigella spp. and enteroinvasive Escherichia coli (EIEC) have already been used to develop live vaccines against tumors. Here, we show that the type 1 secretion system (T1SS) o fi;. coli (α -hemolysin) can be applied to secrete microbial or tumor antigens into mammalian cells and that autolysing Lis tena monocytogenes strains enables the transfer of DNA or RNA encoding functional enzymes into tumor cells. Furthermore, the knowledge of the metabolic processes essential for intra­ cellular replication of these bacteria may help to optimize the construction of virulence-attenuated strains and to detect novel targets that permit the screening for new antibacterial drugs.