Immunomodulation of Monocytes by Probiotic and Selected Lactic Acid Bacteria

Abstract

Some lactic acid bacteria (LAB), especially bacteria belonging to the genus Lactobacillus, are recognized as common inhabitants of the human gastrointestinal tract and have received considerable attention in the last decades due to their postulated health-promoting effects. LAB and probiotic bacteria can modulate the host immune response. However, much is unknown about the mediators and mechanisms responsible for their immunological effect. Here, we present a study using cytokine secretion from the monocytic cell line THP-1 and NF-κB activation in the monocytic cell line U937-3xkB-LUC to elucidate immune stimulating abilities of LAB in vitro. In this study, we investigate both commercially available and potential probiotic LAB strains, and the role of putative surface proteins of L. reuteri using mutants. L. reuteri strains induced the highest cytokine secretion and the highest NF-κB activation, whereas L. plantarum strains and L. rhamnosus GG were low inducers/activators. One of the putative L. reuteri surface proteins, Hmpref0536_10802, appeared to be of importance for the stimulation of THP-1 cells and the activation of NF-κB in U937-3xkB-LUC cells. Live and UV-inactivated preparations resulted in different responses for two of the strains investigated. Our results add to the complexity in the interaction between LAB and human cells and suggest the possible involvement of secreted pro- and anti-inflammatory mediators of LAB. It is likely that it is the sum of bacterial surface proteins and bacterial metabolites and/or secreted proteins that induce cytokine secretion in THP-1 cells and activate NF-κB in U937-3xkB-LUC cells in this study.

Probiotic mixture improves fatty liver disease by virtue of its action on lipid profiles, leptin, and inflammatory biomarkers

“…Based on previous work, we suggest that there is poor communication between LAB, probiotics, and immune cells; we also speculate that pro- and anti-inflammatory mediators are regulated by probiotics and have potential roles in the immune response [26, 27]. Bacterial surface proteins, metabolites, and secreted proteins can stimulate cytokine secretion and can activate NF-κB in cells in vitro [28]. However, the effects of these bacterial products on host cytokine secretion and its blood level require in vivo support and exploration to be better understood; our study employs a mixture of bacteria at various concentrations, and laboratory rats as the experimental in vivo components, to address this.…”

ProbioticLactobacillusStrains Stimulate the Inflammatory Response and Activate Human Macrophages

“…In this context, the immunomodulatory effects of probiotic Lactobacillus strains have also been shown to decrease the inflammatory response under some pathological conditions such as necrotizing enterocolitis and allergies in children [6, 7]. In other in vitro studies, some strains produced an increase in the production of proinflammatory cytokines such as TNF- α , IL-12, and IL-8 whereas others produced increases in the secretion of anti-inflammatory cytokines such as IL-10 [8, 9]. A study by Lopez et al [10] showed that UV-inactivated and live Lactobacillus rhamnosus GG (LGG) are equally effective in decreasing IL-8 in the intestinal epithelium.…”

The effects of inulin as a prebiotic supplement and the synbiotic interactions of probiotics to improve oxalate degrading activity

“…are well‐known probiotics. Lactobacilli are claimed to provide a number of health benefits including anti‐tumour effects (Dasari et al ., ), anti‐cholesterol effects (Tulumoglu et al ., ), immuno‐modulation (Jensen et al ., ), treatment of diarrhoea (Mantegazza et al ., ) and antimicrobial effects against pathogens (Tulumoglu et al ., ). Consuming probiotics is not the only way to re‐establish balance of human health.…”