Secretion of biologically active human interleukin 22 (IL-22) by Lactococcus lactis.

Interleukin-22 (IL-22) participates in the modulation of innate immunity and inflammation. This cytokine has important therapeutic potential, such as with ulcerative colitis, liver and lung injury, and infection, in different animal models. We generated a Lactococcus lactis strain that secretes human IL-22 under the regulation of the nisin-inducible promoter. Identification and secretion of this cytokine was demonstrated using western blots of culture supernatants from IL-22-expressing bacteria. The recombinant IL-22 protein produced by L. lactis was biologically active as determined by its ability to induce IL-10 secretion when co-cultured with a colon epithelial cell line in vitro. We consider this novel strain a promising live vaccine for various therapeutic applications.