Abstract
Recent advances in genetic modification technology show that lactic acid bacteria can constitutively produce functional, eukaryote-derived proteins without any apparent negative effect on bacterial growth and physiology. These bacteria appear capable of surviving and of being physiologically active at the mucosal surfaces of higher eukaryotes. Studies in animal models also suggest that these findings could have a major impact in human medicine. Alongside conceptual proofs, the development of a robust system for biological containment will allow for the examination of genetically modified lactic acid bacteria as vectors of therapeutic protein delivery in human healthcare.