Secretion of biologically active porcine interleukin-2 by Lactococcus lactis

In this study, secretion of two functional recombinant porcine interleukin-2 (rIL-2) proteins by Lactococcus lactis was studied. Two secretion cassettes were constructed in which the secretion was achieved by gene fusion between the lactococcal usp45 secretion signal, a synthetic propeptide and the sequence encoding the mature IL-2. In addition, one of the two secretion cassettes contained the H-domains of L. lactis PrtP. Both of the constructed recombinant IL-2 proteins were found to be secreted in the same quantities, approximately 0.5 mg/l. According to a cell proliferative assay using CTLL-2 cell line the specific biological activities of both purified rIL-2 proteins were found to be of similar levels.