Gene therapy using bacterial vectors

Bacteria can be used for gene therapy via two strategies - either by transfection of eukaryotic host cells using bacteria - bactofection or by alternative gene therapy that does not alter the host genome, but uses the prokaryotic expression system that can be controlled or stopped from outside. While bactofection is optimal for gene substitution and DNA vaccination, alternative gene therapy is suitable for in situ delivery of proteins and treatment with intracellular bactochondria. A specific form of bacteria-mediated gene therapy is the transkingdom RNA interference. In this review advantages and issues related to bacterial vectors as well as the major applications in biomedical research are summarized. Despite numerous published experiments, especially in the treatment of solid tumors and gut infections, the progress in the clinics lags behind and major improvements in the safety and even more in the efficiency of these approaches are needed.