Genetically modified Lactococcus lactis:: novel tools for drug delivery

The dairy bacterium Lactococcus lactis can be genetically engineered to secrete bioactive cytokines. This enabled the development of an entirely novel drug delivery system: topical and active delivery of therapeutic proteins by genetically modified micro-organisms. In mice, intestinal inflammation can be successfully treated with interleukin-10- (IL-10) or trefoil factor-secreting L. lactis. In human application, biological containment is guaranteed by exchange of the gene encoding thymidylate synthase for IL-10. The recombinant strain is now absolutely dependent on exogenous thymidine. Thymidine starvation will irreversibly lead to 'thymidine-less death' induction. This accomplishment has opened applications in human medicine.