Immune-stimulating effects of lactic acid bacteria in vivo and in vitro

• Published in: Proceedings of the Nutrition Society Vol. 69; no. 3; pp. 416 - 420
• Main Authors: Elmadfa, Ibrahim, Klein, Petra, Meyer, Alexa L.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.08.2010
• Subjects: Adult; Bacteria; Caco-2 Cells; Cancer; Cell culture; Cell Differentiation; Conferences; Cultured Milk Products; Cultured Milk Products - immunology; Cytokines; Cytokines - secretion; cytology; Cytotoxicity; Dendritic Cells; Dendritic Cells - cytology; Dendritic Cells - microbiology; Digestive tract; Epithelial cells; Female; Fermented milk products; Food; Functional foods & nutraceuticals; Health promotion; Humans; Immune response; Immunologic Factors; Immunologic Factors - pharmacology; immunology; in vitro studies; Inflammation; Inflammation Mediators; Inflammation Mediators - metabolism; Interleukin 10; Interleukin-10 - secretion; Intestinal Mucosa; Intestinal Mucosa - immunology; Intestinal Mucosa - metabolism; Lactic acid bacteria; Lactobacillus; Lactobacillus - immunology; Lactobacillus delbrueckii; Lactobacillus rhamnosus; Leukocytes, Mononuclear; Leukocytes, Mononuclear - immunology; Leukocytes, Mononuclear - metabolism; Lymphocytes; Lymphocytes T; metabolism; microbiology; Peripheral blood mononuclear cells; pharmacology; Prebiotics; Probiotics; secretion; Session 7: Prebiotics and probiotics usefulness against pathologies; women; yogurt; Young Adult; Probiotics; Lactic acid bacteria; Prebiotics
• ISSN: 0029-6651; 1475-2719; 1475-2719
• DOI: 10.1017/S0029665110001710

The health-promoting effects of lactic acid bacteria (LAB) are well recognised, making them a popular functional food ingredient. Commercially available probiotic products are often promoted as capable of improving immune defences also in healthy subjects. However, while strain-specific differences exist in the effects of LAB, conventional yoghurt bacteria have proved beneficial as well. For comparing the immunological effects of conventional and probiotic LAB, young healthy women received either a commercially available probiotic fermented milk product or a conventional yoghurt for four weeks. Both treatments showed comparable effects resulting in a stronger immunological reaction to stimuli (natural cytotoxicity against cancer cells, mitogen-induced T-lymphocyte activation and stimulated cytokine production). To study the mechanisms behind these effects, conventional (Lactobacillus delbrueckii) and probiotic (Lactobacillus rhamnosus GG), LAB were compared in vitro at the cellular level. Interestingly, L. rhamnosus GG was more potent in inducing maturation of dendritic cells (DC) that play a substantial role in directing the immune response to stimuli. In turn, L. delbrueckii provoked a higher secretion of proinflammatory cytokines as well as IL-10. These effects were, however, observed only after direct incubation of DC and LAB, not when both were separated by a layer of enterocyte-like Caco-2 cells. LAB also induced cytokine secretion in peripheral blood mononuclear cells in a similar manner and this effect was reduced in a Caco-2 cell model, suggesting a modulating influence of gut epithelial cells. While both conventional and probiotic strains modulate the immune response, specific properties may offer therapeutic options in the treatment of certain diseases.