In vitro screening of probiotic lactic acid bacteria and prebiotic glucooligosaccharides to select effective synbiotics

Probiotics and prebiotics have been demonstrated to positively modulate the intestinal microflora and could promote host health. Although some studies have been performed on combinations of probiotics and prebiotics, constituting synbiotics, results on the synergistic effects tend to be discordant in the published works. The first aim of our study was to screen some lactic acid bacteria on the basis of probiotic characteristics (resistance to intestinal conditions, inhibition of pathogenic strains). Bifidobacterium was the most resistant genus whereas Lactobacillus farciminis was strongly inhibited. The inhibitory effect on pathogen growth was strain dependent but lactobacilli were the most effective, especially L. farciminis. The second aim of the work was to select glucooligosaccharides for their ability to support the growth of the probiotics tested. We demonstrated the selective fermentability of oligodextran and oligoalternan by probiotic bacteria, especially the bifidobacteria, for shorter degrees of polymerisation and absence of metabolism by pathogenic bacteria. Thus, the observed characteristics confer potential prebiotic properties on these glucooligosaccharides, to be further confirmed in vivo, and suggest some possible applications in synbiotic combinations with the selected probiotics. Furthermore, the distinctive patterns of the different genera suggest a combination of lactobacilli and bifidobacteria with complementary probiotic effects in addition to the prebiotic ones. These associations should be further evaluated for their synbiotic effects through in vitro and in vivo models.     

Lactic acid bacteria as probiotics for the nose?

Several studies have recently pointed towards an increased occurrence and prevalence of several taxa of the lactic acid bacteria (LAB) in the microbiota of the upper respiratory tract (URT) under healthy conditions versus disease. These include several species of the Lactobacillales such as Lacticaseibacillus casei, Lactococcus lactis and Dolosigranulum pigrum. In addition to physiological studies on their potential beneficial functions and their long history of safe use as probiotics in other human body sites, LAB are thus increasingly to be explored as alternative or complementary treatment for URT diseases. This review highlights the importance of lactic acid bacteria in the respiratory tract and their potential as topical probiotics for this body site. We focus on the potential probiotic properties and adaptation factors that are needed for a bacterial strain to optimally exert its beneficial activity in the respiratory tract. Furthermore, we discuss a range of in silico, in vitro and in vivo models needed to obtain better insights into the efficacy and adaptation factors specifically for URT probiotics. Such knowledge will facilitate optimal strain selection in order to conduct rigorous clinical studies with the most suitable probiotic strains. Despite convincing evidence from microbiome association and in vitro studies, the clinical evidence for oral or topical probiotics for common URT diseases such as chronic rhinosinusitis (CRS) needs further substantiation.     

Robustness of Gut Microbiota of Healthy Adults in Response to Probiotic Intervention Revealed by High-Throughput Pyrosequencing

Probiotics are live microorganisms that potentially confer beneficial outcomes to host by modulating gut microbiota in the intestine. The aim of this study was to comprehensively investigate effects of probiotics on human intestinal microbiota using 454 pyrosequencing of bacterial 16S ribosomal RNA genes with an improved quantitative accuracy for evaluation of the bacterial composition. We obtained 158 faecal samples from 18 healthy adult Japanese who were subjected to intervention with 6 commercially available probiotics containing either Bifidobacterium or Lactobacillus strains. We then analysed and compared bacterial composition of the faecal samples collected before, during, and after probiotic intervention by Operational taxonomic units (OTUs) and UniFrac distances. The results showed no significant changes in the overall structure of gut microbiota in the samples with and without probiotic administration regardless of groups and types of the probiotics used. We noticed that 32 OTUs (2.7% of all analysed OTUs) assigned to the indigenous species showed a significant increase or decrease of ≥10-fold or a quantity difference in >150 reads on probiotic administration. Such OTUs were found to be individual specific and tend to be unevenly distributed in the subjects. These data, thus, suggest robustness of the gut microbiota composition in healthy adults on probiotic administration.     

Role of the probiotic strain Lactobacillus paracasei LMGP22043 carried by artichokes in influencing faecal bacteria and biochemical parameters in human subjects

Aims: To evaluate the positive influence of the probiotic strain Lactobacillus paracasei LMGP22043 carried by artichokes into the human gut with special reference to faecal bacterial balance, short‐chain fatty acid concentrations and enzyme activities in a randomized, double‐blind human trial in comparison with probiotic‐free artichokes (control). Methods: Twenty subjects were randomized into two groups, which consumed daily 180 g of the artichoke product (probiotic or control) during two 15‐day study periods (periods 1 and 2) separated by a 15‐day washout in a crossover manner. Faecal samples were subjected to microbiological and biochemical analyses, and a strain‐specific PCR was performed to monitor the probiotic strain. Results: The probiotic strain, transported by the vegetable matrix, transiently colonized the gut of 17/20 subjects (median 6·87 log CFU g^?1 faeces), antagonized Escherichia coli and Clostridium spp. and increased the genetic diversity of lactic population based on REP‐PCR profiles, mainly after period 1. Conclusions: The probiotic L. paracasei LMGP22043 successfully colonized the human gut and positively influenced faecal bacteria and biochemical parameters. Significance and Impact of the Study: The association of the probiotic L. paracasei with a food carrier rich in fibre can represent a new strategy for favouring a daily supply of probiotics and attracting more consumers to vegetable food fortified with probiotic strains.     

Phytase-Producing Potential and Other Functional Attributes of Lactic Acid Bacteria Isolates for Prospective Probiotic Applications

Wide variations among multifaceted-health benefitting attributes of probiotics fueled investigations on targeting efficacious probiotics. In the current study, lactic acid bacteria (LAB) isolated from poultry gut, feces of rat, chicken, human infants, and fermented foods were characterized for desired probiotic functional properties including the phytase-producing ability which is one of the wanted characteristics for probiotics for potential applications for upgrading animal nutrition, enhancing feed conversion, and minimizing anti-nutritional properties. Among 62 LAB isolates Weissella kimchii R-3 an isolate from poultry gut exhibited substantial phytase-producing ability (1.77 U/ml) in addition to other functional probiotic characteristics viz. hydrophobicity, autoaggregation, coaggregation with bacterial pathogens, and antimicrobial activity against pathogens. Survival of W. kimchii R-3 cells (in free and calcium alginate encapsulated state) was examined sequentially in simulated gastric and intestinal juices. Encapsulated cells exhibited better survival under simulated gut conditions indicating that encapsulation conferred considerable protection against adverse gut conditions. Furthermore, simulated gastric and intestinal juices with pepsin and pancreatin showed higher survival of cells than the juices without pepsin and pancreatin. W. kimchii R-3 due to its significant functional probiotic attributes may have prospective for commercial applications in human/animal nutrition.     

Effect of Soymilk Fermented with Lactobacillus plantarum P-8 on Lipid Metabolism and Fecal Microbiota in Experimental Hyperlipidemic Rats

We recently identified a novel probiotic strain Lactobacillus plantarum P-8 (L. plantarum P-8), which has been characterized in detail with regard to its probiotic potential. In the present study, soymilk fermented with L. plantarum P-8 was examined for its effects on diet-induced hyperlipidemia in Wistar rats. The experimental animals were divided into four groups: control group (C group), model group (M group), soymilk group (SM group) and fermented soymilk group (FSM group). The serum lipid levels, hepatic fat deposition, serum oxidative stress parameters, hepatic marker enzymes levels, organ indices, gut bacteria and fecal fat contents were analyzed. Fermented soymilk reduced the concentration of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) in serum, with a significant elevation in high-density lipoprotein cholesterol (HDL) concentration. Our results also suggested the beneficial effects of fermented soymilk on the liver function, hyperlipidemia-induced oxidative stress and intestinal bacteria. Moreover, fermented soymilk could enhance the fecal excretion of TC, TG and bile acids. These findings demonstrated that soymilk fermented with L. plantarum P-8 was effective in improving the lipid metabolism in hyperlipidemic rats. The hypolipidemic effect of fermented soymilk was partly due to the inhibition of dietary fats absorption and regulation of fecal fats excretion mediated by gut bacteria.     

A Review of the Advancements in Probiotic Delivery: Conventional vs. Non-conventional Formulations for Intestinal Flora Supplementation

Probiotic delivery systems are widely used nutraceutical products for the supplementation of natural intestinal flora. These delivery systems vary greatly in effectiveness to exert health benefits for a patient. Probiotic delivery systems can be categorized into conventional, pharmaceutical formulations, and non-conventional, mainly commercial food-based, products. The degree of health benefits provided by these probiotic formulations varies in their ability to deliver viable, functional bacteria in large enough numbers (effectiveness), to provide protection against the harsh effects of the gastric environment and intestinal bile (in vivo protection), and to survive formulation processes (viability). This review discusses the effectiveness of these probiotic delivery systems to deliver viable functional bacteria focusing on the ability to protect the encapsulated probiotics during formulation process as well as against harsh physiological conditions through formulation enhancements using coatings and polymer enhancements. A brief overview on the health benefits of probiotics, current formulation, patient and legal issues facing probiotic delivery, and possible recommendations for the enhanced delivery of probiotic bacteria are also provided. Newer advanced in vitro analyses that can accurately determine the effectiveness of a probiotic formulation are also discussed with an ideal probiotic delivery system hypothesized through a combination of the two probiotic delivery systems described.     

Probiotics Can Generate FoxP3 T-Cell Responses in the Small Intestine and Simultaneously Inducing CD4 and CD8 T Cell Activation in the Large Intestine

Most studies on probiotics aim to restore intestinal homeostasis to reduce immune-pathology in disease. Of equal importance are studies on how probiotics might prevent or delay disease in healthy individuals. However, knowledge on mechanisms of probiotic actions in healthy individuals is scarce. To gain more insight in how different bacterial strains may modulate the healthy intestinal immune system, we investigated the effect of the food derived bacterial strains L. plantarum WCFS1, L. salivarius UCC118, and L. lactis MG1363, on the intestinal regulatory immune phenotype in healthy mice. All three bacterial strains induced an upregulation of activity and numbers of CD11c⁺ MHCII⁺ DCs in the immune-sampling Peyer’s Patches. Only L. salivarius UCC118 skewed towards an immune regulatory phenotype in the small intestinal lamina propria (SILP). The effects were different in the large intestine lamina propria. L. salivarius UCC118 induced activation in both CD4 and CD8 positive T-cells while L. plantarum WCFS1 induced a more regulatory phenotype. Moreover, L. plantarum WCFS1 decreased the Th1/Th2 ratio in the SILP. Also L. lactis MG1363 had immunomodulatory effects. L. lactis MG1363 decreased the expression of the GATA-3 and T-bet in the SILP. As our data show that contradictory effects may occur in different parts of the gut, it is recommended to study effects of probiotic in different sites in the intestine. Our strain-specific results suggest that unspecified application of probiotics may not be very effective. Our data also indicate that selection of specific probiotic strain activities on the basis of responses in healthy mice may be a promising strategy to specifically stimulate or suppress immunity in specific parts of the intestine.     

In vitro Effects of Prebiotics and Synbiotics on Apis cerana Gut Microbiota

This study aimed to investigate in vitro effects of the selected prebiotics alone, and in combination with two potential probiotic Lactobacillus strains on the microbial composition of Apis cerana gut microbiota and acid production. Four prebiotics, inulin, fructo-oligosaccharides, xylo-oligosaccharides, and isomalto-oligosaccharides were chosen, and glucose served as the carbon source. Supplementation of this four prebiotics increased numbers of Bifidobacterium and lactic acid bacteria while decreasing the pH value of in vitro fermentation broth inoculated with A. cerana gut microbiota compared to glucose. Then, two potential probiotics derived from A. cerana gut at different dosages, Lactobacillus helveticus KM7 and Limosilactobacillus reuteri LP4 were added with isomalto-oligosaccharides in fermentation broth inoculated with A. cerana gut microbiota, respectively. The most pronounced impact was observed with isomalto-oligosaccharides. Compared to isomalto-oligosaccharides alone, the combination of isomalto-oligosaccharides with both lactobacilli strains induced the growth of Bifidobacterium, LAB, and total bacteria and reduced the proliferation of Enterococcus and fungi. Consistent with these results, the altered metabolic activity was observed as lowered pH in in vitro culture of gut microbiota supplemented with isomalto-oligosaccharides and lactobacilli strains. The symbiotic impact varied with the types and concentration of Lactobacillus strains and fermentation time. The more effective ability was observed with IMO combined with L. helveticus KM7. These results suggested that isomalto-oligosaccharides could be a potential prebiotic and symbiotic with certain lactobacilli strains on A. cerana gut microbiota.     

Changes in Protein Synthesis and Morphology during Acid Adaptation of Propionibacterium freudenreichii

Survival of bacteria in changing environments depends on their ability to adapt to abiotic stresses. Microorganisms used in food technology face acid stress during fermentation processes. Similarly, probiotic bacteria have to survive acid stress imposed within the stomach in order to reach the intestine and play a beneficial role. Propionibacteria are used both as cheese starters and as probiotics in human alimentation. Adaptation to low pH thus constitutes a limit to their efficacy. Acid stress adaptation in the probiotic SI41 strain of Propionibacterium freudenreichii was therefore investigated. The acid tolerance response (ATR) was evidenced in a chemically defined medium. Transient exposure to pH 5 afforded protection toward acid challenge at pH 2. Protein neosynthesis was shown to be required for optimal ATR, since chloramphenicol reduced the acquired acid tolerance. Important changes in genetic expression were observed with two-dimensional electrophoresis during adaptation. Among the up-regulated polypeptides, a biotin carboxyl carrier protein and enzymes involved in DNA synthesis and repair were identified during the early stress response, while the universal chaperonins GroEL and GroES corresponded to a later response. The beneficial effect of ATR was evident at both the physiological and morphological levels. This study constitutes a first step toward understanding the very efficient ATR described in P. freudenreichii.     

Bioactives from probiotics for dermal health: functions and benefits

Probiotics have been extensively reviewed for decades, emphasizing on improving general gut health. Recently, more studies showed that probiotics may exert other health‐promoting effects beyond gut well‐being, attributed to the rise of the gut–brain axis correlations. Some of these new benefits include skin health such as improving atopic eczema, atopic dermatitis, healing of burn and scars, skin‐rejuvenating properties and improving skin innate immunity. Increasing evidence has also showed that bacterial compounds such as cell wall fragments, their metabolites and dead bacteria can elicit certain immune responses on the skin and improve skin barrier functions. This review aimed to underline the mechanisms or the exact compounds underlying the benefits of bacterial extract on the skin based on evidences from in vivo and in vitro studies. This review could be of help in screening of probiotic strains with potential dermal enhancing properties for topical applications.     

A synthetic RNA-mediated evolution system in yeast

Laboratory evolution is a powerful approach to search for genetic adaptations to new or improved phenotypes, yet either relies on labour-intensive human-guided iterative rounds of mutagenesis and selection, or prolonged adaptation regimes based on naturally evolving cell populations. Here we present CRISPR- and RNA-assisted in vivo directed evolution (CRAIDE) of genomic loci using evolving chimeric donor gRNAs continuously delivered from an error-prone T7 RNA polymerase, and directly introduced as RNA repair donors into genomic targets under either Cas9 or dCas9 guidance. We validate CRAIDE by evolving novel functional variants of an auxotrophic marker gene, and by conferring resistance to a toxic amino acid analogue in baker''s yeast Saccharomyces cerevisiae with a mutation rate >3,000-fold higher compared to spontaneous native rate, thus enabling the first demonstrations of in vivo delivery and information transfer from long evolving RNA donor templates into genomic context without the use of in vitro supplied and pre-programmed repair donors.     

Screening of Probiotic Candidates in Human Oral Bacteria for the Prevention of Dental Disease

The oral cavity in healthy subjects has a well-balanced microbiota that consists of more than 700 species. However, a disturbance of this balance, with an increase of harmful microbes and a decrease of beneficial microbes, causes oral disorders such as periodontal disease or dental caries. Nowadays, probiotics are expected to confer oral health benefits by modulating the oral microbiota. This study screened new probiotic candidates with potential oral health benefits and no harmful effects on the oral cavity. We screened 14 lactobacillus strains and 36 streptococcus strains out of 896 oral isolates derived from healthy subjects. These bacteria did not produce volatile sulfur compounds or water-insoluble glucan, had higher antibacterial activity against periodontal bacteria, and had higher adherence activity to oral epithelial cells or salivary-coated hydroxyapatite in vitro. We then evaluated the risk of primary cariogenicity and infective endocarditis of the selected oral isolates. As a result, Lactobacillus crispatus YIT 12319, Lactobacillus fermentum YIT 12320, Lactobacillus gasseri YIT 12321, and Streptococcus mitis YIT 12322 were selected because they showed no cariogenic potential in an artificial mouth system and a lower risk of experimental infective endocarditis in a rat model. These candidates are expected as new probiotics with potential oral health benefits and no adverse effects on general health.     

Insight into probiotic properties of lactic acid bacterial endosymbionts of Apis mellifera L. derived from the Polish apiary

Taking into account that fructophilic lactic acid bacteria (FLAB) can play an important role in the health of honey bees and can be used as probiotics, phenotypic properties of probiotic interest of Lactobacillus kunkeei (12 strains) and Fructobacillus fructossus bacteria (2 strains), isolated from Apis mellifera gastrointestinal tract, have been studied. We have evaluated survival of tested FLAB in honey bee gut, their susceptibility to antibiotics (ampicillin, erythromycin, tylosin), cell surface hydrophobicity, auto-aggregation ability, co-aggregation with model pathogenic bacteria, biofilm formation capacity, and effect of studied FLAB, added to sucrose syrup bee diet, on longevity of honey bees. The tested FLAB exhibited good gastrointestinal tract tolerance and high antibiotic susceptibility, which are important criteria in the screening of probiotic candidates. It was also found that all FLAB studied have high cell surface hydrophobicity and fulfil next selection criterion for their use as probiotics. Symbionts of A. mellifera showed also auto- and co-aggregation capacities regarded as valuable features for biofilm formation and inhibition of pathogens adhesion to the bee gut cells. Biofilm-development ability is a desired characteristic of probiotic lactic acid bacteria. As indicated by quantitative crystal violet-stained microplate assay and confocal laser scanning microscopy imaging, all studied A. mellifera gut isolates exhibit a biofilm positive phenotype. Moreover, it was also documented, on honey bees kept in cages, that supplementation of A. mellifera sucrose diet with FLAB decreases mortality and improves significantly longevity of honey bees. Presented research showed that A. mellifera FLAB symbionts are good candidates for application as probiotics.     

The HOG Pathway Is Critical for the Colonization of the Mouse Gastrointestinal Tract by Candida albicans

The opportunistic pathogen Candida albicans is a frequent inhabitant of the human gastrointestinal tract where it usually behaves as a harmless commensal. In this particular niche, it needs to adapt to the different micro environments that challenge its survival within the host. In order to determine those factors involved in gut adaptation, we have used a gastrointestinal model of colonization in mouse to trace the behaviour of fungal cells. We have developed a genetic labelling system based on the complementary spectral properties of the fluorescent proteins GFP and a new C. albicans codon-adapted RFP (dTOM2) that allow a precise quantification of the fungal population in the gut via standard in vitro cultures or flow cytometry. This methodology has allowed us to determine the role of the three MAP kinase pathways of C. albicans (mediated by the MAPK Mkc1, Cek1 or Hog1) in mouse gut colonization via competitive assays with MAPK pathway mutants and their isogenic wild type strain. This approach reveals the signalling through HOG pathway as a critical factor influencing the establishment of C. albicans in the mouse gut. Less pronounced effects for mkc1 or cek1 mutants were found, only evident after 2–3 weeks of colonization. We have also seen that hog1 mutants is defective in adhesion to the gut mucosa and sensitive to bile salts. Finally, we have developed a genetic strategy for the in vivo excision (tetracycline-dependent) of any specific gene during the course of colonization in this particular niche, allowing the analysis of its role during gut colonization.     

Evaluation of The Probiotic Potential of Lactobacillus Delbrueckii Ssp. indicus WDS-7 Isolated from Chinese Traditional Fermented Buffalo Milk In Vitro

The present study aimed to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from Chinese traditional fermented buffalo milk. Out of 22 isolates, 11 were putatively identified as LAB preliminarily. A total of six LAB strains displayed strong adhesion to HT-29 cells and all these strains showed preferable tolerance to artificially simulated gastrointestinal juices. WDS-4, WDS-7, and WDS-18 exhibited excellent antioxidant capacities, including DPPH radical, ABTS⁺ radical, and superoxide anion scavenging activities. Compared with the other two LAB strains, WDS-7 had a stronger inhibition effect on four pathogens. Based on the 16S rRNA gene sequencing and phylogenetic analysis, WDS-7 was identified as Lactobacillus delbrueckii ssp. indicus and selected to assess the potential and safety of probiotics further. The results revealed that WDS-7 strain had a strong capacity for acid production and good thermal stability. WDS-7 strain also possessed bile salt hydrolase (BSH) activity. Compared to LGG, WDS-7 was a greater biofilm producer on the plastic surface and exhibited a better EPS production ability (1.94 mg/ml as a glucose equivalent). WDS-7 was proved to be sensitive in the majority of tested antibiotics and absence of hemolytic activity. Moreover, no production of biogenic amines and β-glucuronidase was observed in WDS-7. The findings of this work indicated that L. delbrueckii ssp. indicus WDS-7 fulfilled the probiotic criteria in vitro and could be exploited for further evaluation in vivo.     

Effect of artemisinin on proliferation and apoptosis-related protein expression in vivo and in vitro

Artemisinin is the first-line drugs for the treatment of malaria. In recent years, a large number of reports showed that artemisinin exhibit anti-tumor activity. In this study, we used C6 glioma cells and rat C6 brain-glioma model to study anti-tumor activity of artemisinin in vivo and in vitro. We found that artemisinin inhibited the proliferation in C6 cells and induced cell cycle arrest and a caspase-3-dependent cell apoptosis. It also inhibited the growth of C6 brain-glioma in vivo and enhanced living state of rat brain-glioma model. These results suggested that artemisinin had significant anti-tumor activities on C6 cells both in vitro and in vivo. Artemisinin might be exploited as a promising clinical anti-cancer drug in future.     

Persistence of the Oral Probiotic Streptococcus salivarius M18 Is Dose Dependent and Megaplasmid Transfer Can Augment Their Bacteriocin Production and Adhesion Characteristics

Bacteriocin-producing probiotic Streptococcus salivarius M18 offers beneficial modulatory capabilities within the oral microbiome, apparently through potent inhibitory activity against potentially deleterious bacteria, such as Streptococcus pyogenes. The oral cavity persistence of S. salivarius M18 was investigated in 75 subjects receiving four different doses for 28 days. Sixty per cent of the subjects already had some inhibitor-producing S. salivarius in their saliva prior to probiotic intervention. Strain M18’s persistence was dependent upon the dose, but not the period of administration. Culture analysis indicated that in some individuals the introduced strain had almost entirely replaced the indigenous S. salivarius, though the total numbers of the species did not increase. Selected subjects showing either high or low probiotic persistence had their salivary populations profiled using Illumina sequencing of the V6 region of the 16S rRNA gene. Analysis indicated that while certain bacterial phenotypes were markedly modulated, the overall composition of the oral microbiome was not modified by the probiotic treatment. Megaplasmids encoding bacteriocins and adhesion factors were transferred in vitro to generate a transconjugant S. salivarius exhibiting enhanced antimicrobial production and binding capabilities to HEp-2 cells. Since no widespread perturbation of the existing indigenous microbiota was associated with oral instillation and given its antimicrobial activity against potentially pathogenic streptococci, it appears that application of probiotic strain M18 offers potential low impact alternative to classical antibiotic prophylaxis. For candidate probiotic strains having relatively poor antimicrobial or adhesive properties, unique derivatives displaying improved probiotic performance may be engineered in vitro by megaplasmid transfer.     

Modulation of the immune response by probiotic strains in a mouse model of gluten sensitivity

Probiotic strains play an important role in modulating activities in the gut-associated lymphoid tissue. Elucidation of the mechanisms that mediate probiotic-driven immunomodulation may facilitate their therapeutic application for specific immune-mediated diseases or for prophylaxis. In this study, we explored the effect of different Lactobacillus spp. and Bifidobacterium lactis in transgenic mice expressing the human DQ8 heterodimer, a HLA molecule linked to Celiac Disease (CD). In vitro analysis on immature bone marrow-derived dendritic cells (iBMDCs) showed that all strains up-regulated surface B7-2 (CD86), indicative of DC maturation, however, with different intensity. No strain induced appreciable levels of IL-10 or IL-12 in iBMDCs, whereas TNF-α expression was essentially elicited by Lactobacillus paracasei and Lactobacillus fermentum. Interestingly, these strains were found also to increase the antigen-specific TNF-α secretion in vivo, following co-administration of probiotic bacteria in mice mucosally immunized with the gluten component gliadin. Together these findings highlighted the ability of probiotics to exert strain-specific inductive rather than suppressive effects both on the innate and adaptive immunity in a mouse model of food antigen sensitivity.