Lactococcus lactis (L. lactis)

Lactococcus lactis is a non-pathogenic, Gram-positive lactic acid bacterium historically utilized in the dairy industry and recognized as Generally Recognized as Safe (GRAS) by regulatory authorities [2, 7]. In modern medicine, it is not a traditional molecular drug target but rather a versatile platform for the development of live biotherapeutic products (LBPs) [1, 11]. Genetically modified strains of L. lactis are engineered to serve as 'cell factories' that express and secrete bioactive molecules, such as anti-inflammatory cytokines or growth factors, directly at mucosal sites like the intestinal lining or oral mucosa [3, 9]. This targeted approach is investigated for treating inflammatory bowel disease, oral mucositis, and autoimmune conditions like Type 1 diabetes [4, 12]. Because L. lactis does not permanently colonize the human gut, it offers a high degree of safety and temporal control over drug delivery in clinical applications [5, 13].

Other names

Streptococcus lactisLactic acid bacteriumMilk-souring bacterium

Lactococcus lactis functions as a live delivery system that produces and secretes therapeutic proteins directly at the site of disease, such as the intestinal mucosa or oral cavity [1, 3]. By expressing molecules like Interleukin-10 or Trefoil Factor 1, engineered L. lactis strains provide localized anti-inflammatory effects and promote tissue repair while minimizing the systemic exposure and side effects typical of parenteral drug administration [11, 13]. Additionally, L. lactis can interact with the host immune system through Toll-like receptors to elicit immunomodulatory effects or serve as a vector for DNA vaccines that induce targeted mucosal and systemic immune responses [4, 10].