Exopolysaccharide-producing Bifidobacterium strains elicit different in vitro responses upon interaction with human cells

Abstract

Probiotic foods intended for human nutrition are gaining economic relevance but it is clear that for the application of new strains scientific and rational selection criteria must be used. In this work, the role of exopolysaccharide (EPS) produced by Bifidobacterium strains in their potential beneficial effect was studied. Two in vitro biological models were used to test the interaction of seventeen strains and their polymers with the host. In general, the EPS-producing bifidobacteria showed good adherence properties to Caco2 and HT29 cell lines which could be of interest for a transitory colonisation of the gut. Most purified EPS were able to slightly stimulate the proliferation of peripheral blood mononuclear cells and their cytokine production pattern, depending on the polymer type tested. In general, neutral high molar mass EPS diminished the immune response, whereas acidic and smaller polymers were able to elicit an increased response. Thus, EPS synthesised in situ during dairy fermentations could be involved in some of the beneficial effects attributed to the EPS-producing bacteria. Probiotic functionality of these strains seems to be related to the physico-chemical characteristics of EPS as is known to occur with the technological properties.

A Single Mutation in the Gene Responsible for the Mucoid Phenotype of Bifidobacterium animalis subsp. lactis Confers Surface and Functional Characteristics

“…lactis DSM10140 and derivative strains was studied with the epithelial intestinal cell line HT29, derived from human colon adenocarcinoma. The cell line maintenance, culture conditions, and reagents were described elsewhere (27). For the adhesion experiments, 10 5 cells ml Ϫ1 were seeded in 48-well plates and incubated to confluence (monolayer of approximately 10 7 cells ml Ϫ1 ), at about 13 days.…”

“…lactis DSM10140 and derivative strains was determined using an in vitro model based on the cocultivation of human peripheral blood mononuclear cells (PBMCs) with the UV-irradiated strains in 48-well plates. The PBMCs were obtained as described by López et al (27). The UV-irradiated bacterial suspensions were prepared as described by López et al (28).…”

“…Plates were incubated for 4 days at 37°C in a 5% CO 2 incubator. Then, 500 l of each well was collected to analyze the cytokine profile as described previously by López et al (27). Transforming growth factor-beta (TGF-␤) levels were determined using a human TGF-␤1 Quantikine enzyme-linked immunosorbent assay (ELISA) kit (R&D Systems, Abingdon, United Kingdom), following the manufacturer's instructions.…”

Genomic Overview and Biological Functions of Exopolysaccharide Biosynthesis in Bifidobacterium spp

“…This is also a common characteristic found in some bifido-EPS, but only a few papers have dealt with this research topic. Using an in vitro approach, López and coworkers (9) have analyzed the immune activity of EPS purified from 13 strains belonging to three Bifidobacterium species (B. animalis subsp. lactis, B. longum, and B. pseudocatenulatum).…”

“…Some EPS have been reported to act as virulence factors in several infectious diseases (3,4), but, in contrast, it has also been shown that bacterial EPS can have a positive impact on human health (5,6). Indeed, the production of EPS by some bacteria with probiotic traits has been tentatively correlated with their capability to modulate the host immune response, eliciting both innate and adaptive responses (7)(8)(9)(10). Additionally, EPS also help the producing bacteria, when they are ingested, to overcome gastrointestinal challenges and to persist for longer periods in the gut (8,11).…”