Lactococcus lactis NZ9000 strain has been used for production of many biologically active proteins, assuming its potential use in future therapies, e.g. IL-12—in the treatment of asthma [26], IL-10 and TGF-β1—inflammatory bowel disease (IBD) [27–29], insulin-like growth factor I (IGF-I)—colitis [30], recombinant mouse heme oxygenase-1 (rmHO-1) [31], and many others [32–34]. The gene discussed is HMOX1; the disease is asthma.