Initial efforts in this field demonstrated methods for Lactococcus lactis secretion of bioactive IL-10, effectively modulating inflammatory symptoms in colitis mouse models [128], and subsequent studies have demonstrated similar results in the mucosal delivery [129] and display [130] of IL-10, IL-22 [131], TGF-β1 [132] and serine protease inhibitors [133–135]. This evidence concerns the gene TGFB1 and colitis.