Lactobacilli and bifidobacteria induce differential interferon-β profiles in dendritic cells.

The health promoting effects of probiotics are well-documented; however, current knowledge on immunostimulatory effects is based on data from a single strain or a limited selection of strains or species. Here, we compared the capacity of 27 lactobacilli and 16 bifidobacteria strains to stimulate bone marrow-derived dendritic cells (DC). Most lactobacilli strains, including Lactobacillus acidophilus, Lactobacillus gasseri, Lactobacillus casei and Lactobacillus plantarum, induced strong IL-12 and TNF-α production and up-regulation of maturation markers.

Lactobacillus acidophilus induces virus immune defence genes in murine dendritic cells by a Toll-like receptor-2-dependent mechanism.

Lactobacilli are probiotics that, among other health-promoting effects, have been ascribed immunostimulating and virus-preventive properties. Certain Lactobacillus spp. have been shown to possess strong interleukin-12 (IL-12) -inducing properties.

Toll-like receptor 2 and nucleotide-binding oligomerization domain-2 play divergent roles in the recognition of gut-derived lactobacilli and bifidobacteria in dendritic cells.

The gut microbiota is vital in the maintenance of homeostasis in the gut immune system. Its diversity and composition play major roles in relation to allergies and inflammatory bowel diseases, and administration of lactic acid bacteria (LAB), such as lactobacilli and bifidobacteria, has positive effects on these pathologies. However, the mechanisms behind the beneficial effects are largely unknown.

Epithelial cells prime the immune response to an array of gut-derived commensals towards a tolerogenic phenotype through distinct actions of thymic stromal lymphopoietin and transforming growth factor-beta.

Humans and other mammals coexist with a diverse array of microbes colonizing the intestine, termed the microflora. The relationship is symbiotic, with the microbes benefiting from a stable environment and nutrient supply, and the host gaining competitive exclusion of pathogens and continuously maintenance of the gut immune homeostasis. Here we report novel crosstalk mechanisms between the human enterocyte cell line, Caco2, and underlying human monocyte-derived DC in a transwell model where Gram-positive (G+) commensals prevent Toll-like receptor-4 (TLR4)-dependent Escherichia coli-induced semimaturation in a TLR2-dependent fashion.

Lactic acid bacteria inducing a weak interleukin-12 and tumor necrosis factor alpha response in human dendritic cells inhibit strongly stimulating lactic acid bacteria but act synergistically with gram-negative bacteria.

The development and maintenance of immune homeostasis indispensably depend on signals from the gut flora. Lactic acid bacteria (LAB), which are gram-positive (G+) organisms, are plausible significant players and have received much attention. Gram-negative (G-) commensals, such as members of the family Enterobacteriaceae, may, however, be immunomodulators that are as important as G+ organisms but tend to be overlooked.