Immune-modulating effects in mouse dendritic cells of lactobacilli and bifidobacteria isolated from individuals following omnivorous, vegetarian and vegan diets

Abstract

Abbreviations used in this paper: DCs, dendritic cells; TPY, trypticase-phytone-yeast extract; MRS, de Man, Rogosa and Sharpe medium; GM-CSF, granulocyte-macrophage colony-stimulating factor; SCFAs, short-chain fatty acids; LAB, lactic acid bacteria; CTLA-4, cytotoxic T-lymphocyte antigen 4. *Manuscript Click here to view linked References AbstractLactobacilli and bifidobacteria play a primary role in modulation of gut immunity. By considering that microbiota composition depends on various factors, including diet, we asked whether functional differences could characterize faecal populations of lactobacilli and bifidobacteria isolated from individuals with different dietary habits. 155 healthy volunteers who followed omnivorous, ovo-lacto-vegetarian or vegan diets were recruited at four Italian centres (Turin, Parma, Bologna and Bari). Faecal samples were collected; lactobacilli and bifidobacteria were isolated on selective media and their immunomodulatory activity was tested in mouse dendritic cells (DCs). Pre-incubation with lactobacilli increased LPS-induced expression of the maturation markers CD80 and CD86, whereas pre-incubation with bifidobacteria decreased such expression.Analysis of the cytokine profile indicated that strains of both genera induced down-regulation of IL-12 and up-regulation of IL-10, whereas expression of TNF-was not modulated. Notably, analysis of anti-inflammatory potential (IL-10/IL-12 ratio) showed that lactobacilli evoked a greater antiinflammatory effect than did bifidobacteria in the omnivorous group (P<0.05). We also found significantly reduced anti-inflammatory potential in the bacterial strains volunteers in comparison with those from the cognate groups from the other centres. In conclusion, lactobacilli and bifidobacteria showed a genus-specific ability of modulating in vitro innate immunity associated with a specific dietary habit. Furthermore, the geographical area had a significant impact on the anti-inflammatory potential of some components of faecal microbiota.

Immunomodulation and Generation of Tolerogenic Dendritic Cells by Probiotic Bacteria in Patients with Inflammatory Bowel Disease

“…This is supported by the study by Wang et al who found that the administration of L. reuteri inhibits the development and progression of immune checkpoint blocker (ICB)-induced colitis (which enhances antitumor immunity by blocking CTLA-4), and that the depletion of Lactobacillus by antibiotic therapy worsens ICB colitis [21]. Our findings are also consistent with the observations of Luongo et al who found that pre-incubation of murine DCs with lactobacilli increases the expression of the maturation markers and induces an anti-inflammatory effect [22]. However, these authors also found that bifidobacteria decreases the costimulatory surface molecule expression, which is in contrast to our results.…”

Akkermansia muciniphila Exerts Strain-Specific Effects on DSS-Induced Ulcerative Colitis in Mice

“…Although the evidence of functional differences between different strains of this species is abundant, the factors that contribute to the specificity of these strains remain unclear. The genetic background of the bacterial strains is considered to have an important influence on the functional specificity of probiotics ( Ribbera et al., 2013 ; Luongo et al., 2017 ; Wang et al., 2017 ). A previous report revealed that although the genomes of A. muciniphila ATCC BAA-835 and A. muciniphila 139 are highly similar, they contain strain-specific genes that result in a differing ability to relieve gut inflammation and restore intestinal flora in chronic colitis ( Zhai et al., 2019 ).…”

Bifidobacteria and Their Molecular Communication with the Immune System

“…The immunomodulation potential of bifidobacteria has also been studied on enterocytes including Caco-2 or HT29 cell models ( Bahrami et al, 2011 ; Chichlowski et al, 2012 ; Khokhlova et al, 2012 ; Arboleya et al, 2015 ; Sánchez et al, 2015 ; Luongo et al, 2017 ). Although the immune response of epithelial cells is much more limited than the one exerted by specialized immune cells, enterocytes are more directly exposed to the intestinal milieu and are considered to play a key role in initiating the bifidobacteria–host interactions.…”