L. Rhamnosus GG Research Articles

Comparison of the Immunomodulatory Properties of Three Probiotic Strains of Lactobacilli Using Complex Culture Systems: Prediction for In Vivo Efficacy

BackgroundWhile the use of probiotics to treat or prevent inflammatory bowel disease (IBD) has been proposed, to this point the clinical benefits have been limited. In this report we analyzed the immunological activity of three strains of Lactobacillus to predict their in vivo efficacy in protecting against experimental colitis.Methodology/Principal FindingsWe compared the immunological properties of Lactobacillus plantarum NCIMB8826, L. rhamnosus GG (LGG), L. paracasei B21060 and pathogenic Salmonella typhimurium (SL1344). We studied the stimulatory effects of these different strains upon dendritic cells (DCs) either directly by co-culture or indirectly via conditioning of an epithelial intermediary. Furthermore, we characterized the effects of these strains in vivo using a Dextran sulphate sodium (DSS) model of colitis.We found that the three strains exhibited different abilities to induce inflammatory cytokine production by DCs with L. plantarum being the most effective followed by LGG and L. paracasei. L. paracasei minimally induced the release of cytokines, while it also inhibited the potential of DCs to both produce inflammatory cytokines (IL-12 and TNF-α) and to drive Th1 T cells in response to Salmonella. This effect on DCs was found under both direct and indirect stimulatory conditions – i.e. mediated by epithelial cells - and was dependent upon an as yet unidentified soluble mediator. When tested in vivo, L. plantarum and LGG exacerbated the development of DSS-induced colitis and caused the death of treated mice, while, conversely L. paracasei was protective.ConclusionsWe describe a new property of probiotics to either directly or indirectly inhibit DC activation by inflammatory bacteria. Moreover, some immunostimulatory probiotics not only failed to protect against colitis, they actually amplified the disease progression. In conclusion, caution must be exercised when choosing a probiotic strain to treat IBD.

Dietary Supplementation with Lactic Acid Bacteria Attenuates the Development of Atopic Dermatitis-Like Skin Lesions in NC/Nga Mice in a Strain-Dependent Manner

Background: Dietary supplementation with lactic acid bacteria (LAB) is a potential approach to the prevention and manipulation of allergic diseases such as atopic dermatitis (AD). However, the influence of different bacterial strains and their immunomodulating capacities is still largely unknown. Methods: AD-like skin lesions were induced by sensitization to and repeated challenges with picrylchloride in the Th2-skewed NC/Nga mouse strain. The effects of LAB supplementation were assessed over time by monitoring clinical scores and plasma IgE levels. In some cases, mast cell infiltration, cutaneous hypersensitivity responses and cytokine mRNA expression in auricles were also examined. Additionally, cytokine production in vitro and cytokine mRNA accumulation in major lymphoid tissues were measured, comparing Lactobacillus paracasei KW3110 with L. rhamnosus GG (LGG). Results: Supplementation with KW3110 significantly reduced the development of AD-like skin lesions, accompanied by less mast cell infiltration and lower plasma IgE levels. KW3110 also suppressed immediate hypersensitivity reactions and IL-4 mRNA expression in the auricles. These preventive effects sustained when supplementation was terminated; moreover, inhibitory effects were also observed even when supplementation was initiated after the onset of symptoms. In accordance with its effects on IL-12 and IL-4 production in vitro, KW3110 prevented the emergence of clinical symptoms more effectively than LGG in vivo. Conclusions: Supplementation with KW3110 significantly attenuated the onset and exacerbation of AD-like symptoms in NC/Nga mice. The effects were more prominent than those obtained with LGG, suggesting the importance of differences between LAB strains and their immunomodulating capacity.