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Aging is a physiological and immunological process involving the deterioration of human health, characterised by the progressive alteration of organs and their functions. The speed and extent of such decline are dependent on lifestyle, environment, and genetic factors. Moreover, with advancing age, humans become progressively more fragile and prone to acute and chronic diseases. Although the intestinal microbiota is predisposed to perturbations that accompany aging and frailty, it is generally accepted that the gut microbiota engages in multiple interactions that affect host health throughout the host life span. In the current study, an exhaustive in silico investigation of gut-associated bifidobacteria in healthy individuals from birth to old age revealed that Bifidobacterium longum subsp. longum is the most prevalent member, especially during infancy and in centenarians. Moreover, B. longum subsp. longum genome reconstruction and strain tracing among human gut microbiomes allowed the identification of prototypes of this taxon in the human gut microbiota of healthy elderly individuals. Such analyses guided culturomics attempts to isolate B. longum subsp. longum strains that matched the genomic content of B. longum subsp. longum prototypes from healthy elderly individuals. The molecular effects of selected B. longum subsp. longum strains on the human host were further investigated using in vitro microbe-host interactions, revealing differences in the host immune system transcriptome, with a reduction in gene expression of inflammation-related cytokines. These intriguing findings support the potential anti-aging effects of elderly associated prototypes of B. longum subsp. longum.

Sensing of the intestinal microbiota by the host immune system is important to induce protective immune responses. Hence, modification of the gut microbiota might be able to prevent or treat allergies, mediated by proinflammatory Th2 immune responses. The aim was to investigate the ex vivo immunomodulatory effects of the synbiotics Pollagen® and Kallergen®, containing the probiotic bacterial strains Lactobacillus, Lacticaseibacillus and Bifidobacterium, in the context of grass pollen allergy. Peripheral blood mononuclear cells (PBMCs) from grass pollen-allergic patients and healthy controls were stimulated with grass pollen extract (GPE) and synbiotics and Gata3 expression and cytokine secretion analyzed. Monocyte-derived dendritic cells (MoDCs) cells were matured in the presence of GPE and synbiotics, co-cultured with autologous naïve T cells and maturation markers and cytokine secretion analyzed. GPE stimulation of PBMCs from grass pollen-allergic patients resulted in a significant higher production of the Th2 cytokines IL-4, IL-5, IL-9 and IL-13 compared to healthy controls. Gata3 + CD4 + T cell induction was independent of the allergic status. The synbiotics promoted IL-10 and IFN-γ secretion and downregulated the GPE-induced Th2-like phenotype. Co-culturing naïve T cells with MoDCs, matured in the presence of GPE and synbiotics, shifted the GPE-induced Th2 cytokine release towards Th1-Th17-promoting conditions in allergic subjects. The investigated synbiotics are effective in downregulating the GPE-induced Th2 immune response in PBMCs from grass pollen-allergic patients as well as in autologous MoDC-T cell stimulation assays. In addition to increased IL-10 release, the data indicates a shift from a Th2- to a more Th1- and Th17-like phenotype., (© 2022. The Author(s).)

In a previous study, we uncovered three immune-responsive patterns of gut microbes using an in vitro mesenteric lymph node cell suspension model, abbreviated as the MLN model hereafter. We used Akkermansia muciniphila and Clostridium butyricum as the first group directly inducing an immune response, Bifidobacterium sp. and Bacteroides sp. as the second group evoking an immune response with the help of stimuli (anti-CD3 and anti-CD28 antibodies), and Lactobacillus sp. as the third group blunting the immune response with or without stimuli. Our group previously clarified the immune-activation characteristics of A. muciniphila and linked its in vivo immune induction effect in GF and SPF mice under homeostasis. In the present study, we supplemented the characteristics of C. butyricum and B. bifidum in the in vitro MLN model and addressed the specific elements of the model. Finally, we used an in vivo TNBS-challenge model to show the functional differences between these species with different response patterns in vitro. The results showed that C. butyricum and B. bifidum evoked an immune response in vitro in a dose-dependent and strain-unique manner. Although TLR2, rather than TLR4, is indispensable for immune activation in the present in vitro model, it may not involve interaction between TLR2 and bacterial ligands. Like the PBMC model, the present in vitro MLN model is highly dependent on cell resources and should be given more attention when used to conduct a quantitative comparison. Finally, a mixture of two strong immunogenic strains, A. muciniphila and C. butyricum , significantly increased the mortality of TNBS-challenged (2,4,6-trinitrobenzene sulfonic acid, TNBS) mice, indicating a possible link between the in vitro MLN model and in vivo functional evaluation. However, more evidence is needed to clarify the associations and underlying mechanisms.

The potential therapeutic effects of probiotic bacteria in rheumatoid arthritis (RA) remain controversial. Thus, this study aimed to discover potential therapeutic bacteria based on the relationship between the gut microbiome and rheumatoid factor (RF) in RA. Bacterial genomic DNA was extracted from the fecal samples of 93 RA patients and 16 healthy subjects. Microbiota profiling was conducted through 16S rRNA sequencing and bioinformatics analyses. The effects of Bifidobacterium strains on human peripheral blood mononuclear cells and collagen-induced arthritis (CIA) mice were assessed. Significant differences in gut microbiota composition were observed in patients with different RF levels. The relative abundance of Bifidobacterium and Collinsella was lower in RF-high than in RF-low and RF-negative RA patients, while the relative abundance of Clostridium of Ruminococcaceae family was higher in RF-high than in RF-low and RF-negative patients. Among 10 differentially abundant Bifidobacterium , B. longum RAPO exhibited the strongest ability to inhibit IL-17 secretion. Oral administration of B. longum RAPO in CIA mice, obese CIA, and humanized avatar model significantly reduced RA incidence, arthritis score, inflammation, bone damage, cartilage damage, Th17 cells, and inflammatory cytokine secretion. Additionally, B. longum RAPO significantly inhibited Th17 cells and Th17-related genes- IL-17A , IRF4 , RORC , IL-21 , and IL-23R -in the PBMCs of rheumatoid arthritis patients. Our findings suggest that B. longum RAPO may alleviate RA by inhibiting the production of IL-17 and other proinflammatory mediators. The safety and efficacy of B. longum RAPO in patients with RA and other autoimmune disorders merit further investigation., Competing Interests: Authors YJ, S-JP, MP, BK and GJ was employed by company BIFIDO Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Jeong, Jhun, Lee, Na, Choi, Cho, Lee, Lee, Park, You, Kim, Park, Kwon, Cho, Ji and Park.)

Delivery by cesarean section (CS) is linked to an increased incidence of food allergies in children and affects early gut microbiota colonization. Furthermore, emerging evidence has connected disordered intestinal microbiota to food allergies. Here, we investigated the impact of CS on a rat model for food allergy to ovalbumin (OVA). Rats delivered by CS were found to be more responsive to OVA sensitization than vaginally born ones, displaying a greater reduction in rectal temperature upon challenge, worse diarrhea, and higher levels of OVA-specific antibodies and histamine. 16S rRNA sequencing of feces revealed reduced levels of Lactobacillus and Bifidobacterium in the CS rats. Preventative supplementation with a probiotic combination containing Lactobacillus and Bifidobacterium could protect CS rats against an allergic response to OVA, indicating that the microbiota dysbiosis contributes to CS-related response. Additionally, probiotic intervention early in life might help to rebuild aberrant Th2 responses and tight junction proteins, both of which have been linked to CS-related high allergic reactions. Taken together, this study shows that disordered intestinal microbiota plays an essential role in the pathogenesis of food allergy mediated by CS. More importantly, interventions that modulate the microbiota composition in early life are therapeutically relevant for CS-related food allergies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Jin, Li, Xia, Li, Zhao, Li, Li, Li, Zhou, Fu, Li and Li.)

Objective: To present a comprehensive, clinically focused scoping review of therapeutic agents and practices comprising the future of allergic rhinitis (AR) management., Data Sources: A review of the published literature was performed using the PubMed database, published abstracts, and virtual presentations from scientific meetings and posted results on ClinicalTrials.gov., Study Selections: Primary manuscripts with trial results, case reports, case series, and clinical trial data from ClinicalTrials.gov, PubMed, and articles highlighting expert perspectives on management of AR were selected., Results: Telemedicine, social media, and mHealth facilitate integrated care for AR management. Pharmacotherapy remains the standard of care for AR management; however, treatment combinations are recommended. Intralymphatic immunotherapy and peptide immunotherapy are the most promising new allergen immunotherapy options. Studies of targeted biologics for AR are ongoing. Probiotics may be beneficial for AR management, particularly Bifidobacterium spp, and as an add-on to allergen immunotherapy., Conclusion: AR is a chronic and often comorbid condition that requires integrated care for optimal management. New formulations and combinations of existing AR therapies are the most promising and merit future research., (Copyright © 2021 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Bifidobacterium strains can provide several health benefits, such as antimicrobial and immunomodulatory effects. Some strains inhibit growth or cell adhesion of pathogenic bacteria, including multidrug-resistant bacteria, and their antibacterial activity can be intensified when combined with certain antibiotics. In addition, some strains of bifidobacteria reduce viral infectivity, leading to less epithelial damage of intestinal tissue, lowering the virus shedding titer, and controlling the release of antiviral substances. Furthermore, bifidobacteria can modulate the immune system by increasing immunoglobulins, and inducing or reducing pro- or antiinflammatory cytokines, respectively. In particular, these anti-inflammatory effects are helpful in the treatment of patients who are already suffering from infection or inflammatory diseases. This review summarizes the antimicrobial effects and mechanisms, and immunomodulatory effects of Bifidobacterium strains, suggesting the potential of bifidobacteria as an alternative or complementary treatment option.

Immune checkpoint-blocking antibodies that attenuate immune tolerance have been used to effectively treat cancer, but they can also trigger severe immune-related adverse events. Previously, we found that Bifidobacterium could mitigate intestinal immunopathology in the context of CTLA-4 blockade in mice. Here we examined the mechanism underlying this process. We found that Bifidobacterium altered the composition of the gut microbiota systematically in a regulatory T cell (Treg)-dependent manner. Moreover, this altered commensal community enhanced both the mitochondrial fitness and the IL-10-mediated suppressive functions of intestinal Tregs, contributing to the amelioration of colitis during immune checkpoint blockade., Competing Interests: The authors declare no competing interest., (Copyright © 2020 the Author(s). Published by PNAS.)

Purpose of Review: The body's largest microbial community, the gut microbiome, is in contact with mucosal surfaces populated with epithelial, immune, endocrine and nerve cells, all of which sense and respond to microbial signals. These mutual interactions have led to a functional coevolution between the microbes and human physiology. Examples of coadaptation are anaerobes Bifidobacteria and Bacteroides, which have adjusted their metabolism to dietary components of human milk, and infant immune development, which has evolved to become reliant on the presence of beneficial microbes. Current research suggests that specific composition of the early-life gut microbiome aligns with the maturation of host immunity. Disruptions of natural microbial succession patterns during gut colonization are a consistent feature of immune-mediated diseases, including atopy and asthma., Recent Findings: Here, we catalog recent birth cohorts documenting associations between immune dysregulation and microbial alterations, and summarize the evidence supporting the role of the gut microbiome as an etiological determinant of immune-mediated allergic diseases., Summary: Ecological concepts that describe microbial dynamics in the context of the host environment, and a portray of immune and neuroendocrine signaling induced by host-microbiome interactions, have become indispensable in describing the molecular role of early-life microbiome in atopy and asthma susceptibility.

Bifidobacterium animalis subsp. lactis IPLA 20020 and Lactobacillus gasseri IPLA 20212, two strains isolated from human samples, were evaluated for safety and influence over the intestinal microbiota and cytokine production by the intestinal tissue of adult BALB/c mice. Mice were divided into four groups receiving during 8 days PBS or a suspension of each strain, prepared fresh or lyophilized (bifidobacteria), at an amount of 4x10 8 viable cells/day. This dose could be comparable to the probiotic intake of a human adult who consumed about 100-200 mL of functional fermented milk per day, considering the usual level of probiotics in commercial products. No microbial translocation to liver or alterations in food intake, weight, and behavior were observed in treated mice. Intestinal content of secretory immunoglobulin A (s-IgA) was not affected, discarding any adverse effect on the mucosa-associated immunity. The profile of intestinal proinflammatory/regulatory cytokines after intervention evidenced that the microbial strain administered and its cellular state (fresh or lyophilized) as well as the host tissue analyzed (small or large intestine) influenced the immune response and suggests a moderate shift towards a T helper 1 profile (Th1) in the large intestine after the administration of both strains. Changes on relative levels of some intestinal microbial groups were evidenced after intervention. It is noteworthy that butyrate was positively associated with a balanced pro-Th1 immune response. Therefore, B. animalis subsp . lactis IPLA20020 and L. gasseri IPLA 20212 could be considered potential probiotic candidates to be included in functional foods for balancing the intestinal immune response.

Previously, we reported that the non-viable immunomodulatory Bifidobacterium infantis MCC12 and Bifidobacterium breve MCC1274 strains (paraimmunobiotic bifidobacteria) were able to increase the protection against rotavirus infection in bovine intestinal epithelial (BIE) cells. In order to gain insight into the influence of paraimmunobiotic bifidobacteria on the innate antiviral immune response of BIE cells, their effect on the transcriptomic response triggered by Toll-like receptor 3 (TLR3) activation was investigated. By using microarray technology and qPCR analysis, we obtained a global overview of the immune genes involved in the innate antiviral immune response in BIE cells. Activation of TLR3 by poly(I:C) in BIE cells significantly increased the expression of interferon (IFN)-α and IFN-β, several interferon-stimulated genes, cytokines, and chemokines. It was also observed that both paraimmunobiotic bifidobacteria differently modulated immune genes expression in poly(I:C)-challenged BIE cells. Most notable changes were found in genes involved in antiviral defence (IFN-β, MX1, OAS1X, MDA5, TLR3, STAT2, STAT3), cytokines (interleukin (IL)-6), and chemokines (CCL2, CXCL2, CXCL6) that were significantly increased in bifidobacteria-treated BIE cells. B. infantis MCC12 and B. breve MCC1274 showed quantitative and qualitative differences in their capacities to modulate the innate antiviral immune response in BIE cells. B. breve MCC1274 was more efficient than the MCC12 strain to improve the production of type I IFNs and antiviral factors, an effect that could be related to its higher ability to protect against rotavirus replication in BIE cells. Interestingly, B. infantis MCC12 showed a remarkable anti-inflammatory effect. The MCC12 strain was more efficient to reduce the expression of inflammatory cytokines and chemokines (IL-16, IL-20, CX3CL1) when compared with B. breve MCC1274. These results provided valuable information for the deeper understanding of the antiviral immune response of intestinal epithelial cells as well as the host-paraimmunobiotic interaction in the bovine host.

Discoveries made in the past 5 years indicate that the composition of the intestinal microbiota has a major influence on the effectiveness of anticancer immunosurveillance and thereby contributes to the therapeutic activity of immune-checkpoint inhibitors that target cytotoxic T lymphocyte protein 4 (CTLA-4) or the programmed cell death protein 1 (PD-1)-programmed cell death 1 ligand 1 (PD-L1) axis, as well as the activity of immunogenic chemotherapies. Herein, we highlight some of the bacteria, such as Akkermansia muciniphila, Bacteroides fragilis, Bifidobacterium spp. and Faecalibacterium spp., that have been associated with favourable anticancer immune responses in both preclinical tumour models and patients with cancer. Importantly, these bacteria also seem to have a positive influence on general health, thus reducing the incidence of metabolic disorders and a wide range of chronic inflammatory pathologies. We surmise that a diverse and propitious microbial ecosystem favours organismal homeostasis, particularly at the level of the cancer-immune dialogue.

Objective: Effect of a probiotic on the gut microbiome and peripheral immune function in healthy controls and relapsing-remitting multiple sclerosis (MS) patients., Methods: MS patients (N = 9) and controls (N = 13) were orally administered a probiotic containing Lactobacillus, Bifidobacterium, and Streptococcus twice-daily for two months. Blood and stool specimens were collected at baseline, after completion of the 2-month treatment, and 3 months after discontinuation of therapy. Frozen peripheral blood mononuclear cells (PBMCs) were used for immune cell profiling. Stool samples were used for 16S rRNA profiling and metabolomics., Results: Probiotic administration increased the abundance of several taxa known to be depleted in MS such as Lactobacillus. We found that probiotic use decreased the abundance of taxa previously associated with dysbiosis in MS, including Akkermansia and Blautia. Predictive metagenomic analysis revealed a decrease in the abundance of several KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways associated with altered gut microbiota function in MS patients, such as methane metabolism, following probiotic supplementation. At the immune level, probiotic administration induced an anti-inflammatory peripheral immune response characterized by decreased frequency of inflammatory monocytes, decreased mean fluorescence intensity (MFI) of CD80 on classical monocytes, as well as decreased human leukocyte antigen (HLA) D related MFI on dendritic cells. Probiotic administration was also associated with decreased expression of MS risk allele HLA-DQA1 in controls. Probiotic-induced increase in abundance of Lactobacillus and Bifidobacterium was associated with decreased expression of MS risk allele HLA.DPB1 in controls., Interpretation: Our results suggest that probiotics could have a synergistic effect with current MS therapies. Ann Neurol 2018., (© 2018 American Neurological Association.)

Antibodies that attenuate immune tolerance have been used to effectively treat cancer, but they can also trigger severe autoimmunity. To investigate this, we combined anti-CTLA-4 treatment with a standard colitis model to give mice a more severe form of the disease. Pretreatment with an antibiotic, vancomycin, provoked an even more severe, largely fatal form, suggesting that a Gram-positive component of the microbiota had a mitigating effect. We then found that a commonly used probiotic, Bifidobacterium , could largely rescue the mice from immunopathology without an apparent effect on antitumor immunity, and this effect may be dependent on regulatory T cells., Competing Interests: The authors declare no conflict of interest.

Internally transcribed spacer (ITS) rRNA profiling is a novel tool for detailed analysis of microbial populations at low taxonomic ranks. Here we exploited this approach to explore species-level biogeography of the Bifidobacterium genus across 291 adult mammals. These include humans and 13 other primates, domesticated animals, such as dogs, cats, cows, sheep, goats, horses and pigs, and 46 additional species. The collected profiles revealed the presence of 89 putative novel bifidobacterial taxa in addition to 45 previously described species. Remarkably, in contrast to what is currently known for many gut commensals, we did not observe host-specialization among bifidobacterial species but rather their widespread distribution across mammals. Moreover, ITS rRNA profiling of wild relatives of domesticated dogs, rabbits and pigs clearly indicates that domestication and close contact with humans have impacted on the composition of the fecal bifidobacterial population. These data were complemented by analysis of bifidobacterial communities in milk of eight mammalian families, showing that bifidobacteria represent prototypical early gut microbiota members which are inherited by newborns from their lactating mother. Thus this study highlights the role of bifidobacteria as pioneering gut colonizers of a wide range of mammals.

Lactobacilli 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-α was not modulated. Notably, analysis of anti-inflammatory potential (IL-10/IL-12 ratio) showed that lactobacilli evoked a greater anti-inflammatory effect than did bifidobacteria in the omnivorous group (P<0.05). We also found significantly reduced anti-inflammatory potential in the bacterial strains isolated from Bari's 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., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Bifidobacteria are members of the intestinal microbiota of mammals and other animals, and some strains are able to exert health-promoting effects. The genus Bifidobacterium belongs to the Actinobacteria phylum. Firmicutes , Bacteroidetes , and Actinobacteria constitute the most abundant phyla in the human intestinal microbiota, Firmicutes and Bacteroidetes being predominant in adults, and Actinobacteria in breast-fed infants, where bifidobacteria can reach levels higher than 90% of the total bacterial population. They are among the first microbial colonizers of the intestines of newborns, and play key roles in the development of their physiology, including maturation of the immune system and use of dietary components. Indeed, some nutrients, such as human milk oligosaccharides, are important drivers of bifidobacterial development. Some Bifidobacterium strains are considered probiotic microorganisms because of their beneficial effects, and they have been included as bioactive ingredients in functional foods, mainly dairy products, as well as in food supplements and pharma products, alone, or together with, other microbes or microbial substrates. Well-documented scientific evidence of their activities is currently available for bifidobacteria-containing preparations in some intestinal and extraintestinal pathologies. In this review, we focus on the role of bifidobacteria as members of the human intestinal microbiota and their use as probiotics in the prevention and treatment of disease.

Several types of vaccine-delivering tumor-associated antigens (TAAs) have been developed in basic and clinical research. Wilms' tumor 1 (WT1), identified as a gene responsible for pediatric renal neoplasm, is one of the most promising TAA for cancer immunotherapy. Peptide and dendritic cell-based WT1 cancer vaccines showed some therapeutic efficacy in clinical and pre-clinical studies but as yet no oral WT1 vaccine can be administrated in a simple and easy way. In the present study, we constructed a novel oral cancer vaccine using a recombinant Bifidobacterium longum displaying WT1 protein. B. longum 420 was orally administered into mice inoculated with WT1-expressing tumor cells for 4 weeks to examine anti-tumor effects. To analyze the WT1-specific cellular immune responses to oral B. longum 420, mice splenocytes were isolated and cytokine production and cytotoxic activities were determined. Oral administrations of B. longum 420 significantly inhibited WT1-expressing tumor growth and prolonged survival in mice. Immunohistochemical study and immunological assays revealed that B. longum 420 substantially induced tumor infiltration of CD4 + T and CD8 + T cells, systemic WT1-specific cytokine production, and cytotoxic activity mediated by WT1-epitope specific cytotoxic T lymphocytes, with no apparent adverse effects. Our novel oral cancer vaccine safely induced WT1-specific cellular immunity via activation of the gut mucosal immune system and achieved therapeutic efficacy with several practical advantages over existing non-oral vaccines.

Enterocytes are actively involved in the defense against pathogens and they limit penetration of commensal microbes into tissues. They also have an important role in gut immunity as enterocytes confer mucosal dendritic cell specialisation. On the other hand, the microbiota is directly involved in the development and modulation of the intestinal immune system. Particularly, lactobacilli and bifidobacteria play a primary role in shaping the immune response. We further explored this issue by evaluating whether functional differences in Caco-2 cells could characterise faecal populations of lactobacilli (155 samples) and bifidobacteria (110 samples) isolated from three dietary cohorts (omnivores, ovo-lacto-vegetarians and vegans) recruited at four Italian centres (Turin, Parma, Bologna and Bari). According to our findings, tested bacteria were unable to modulate expression of IL-8, IL-10, TGF-β or thymic stromal lymphopoietin (TSLP) cytokines in unstimulated Caco-2 cells. Conversely, in phorbol 12-myristate 13-acetate and ionomycin (PMA/Io) stimulated Caco-2 cells, lactobacilli from the omnivorous group and all bifidobacteria significantly down-regulated IL-8. Notably, both genera also lowered the TSLP expression in stimulated Caco-2 cells, regardless of the diet regimen. By further examining these data on the basis of geographical origin, we found that lactobacilli from the vegetarian group recruited in Bari, significantly up-regulated this cytokine. In conclusion, we highlighted a peculiar immune-modulatory activity profile for lactobacilli on enterocytes undergoing a stimulatory signal, which was associated with a specific dietary habit. Furthermore, the geographical area had a significant impact on the inflammatory potential of members of the Lactobacillus genus., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Age-associated immunological dysfunction (immunosenescence) is closely linked to perturbation of the gut microbiota. Here, we investigated whether syringaresinol (SYR), a polyphenolic lignan, modulates immune aging and the gut microbiota associated with this effect in middle-aged mice. Compared with age-matched control mice, SYR treatment delayed immunosenescence by enhancing the numbers of total CD3 + T cells and naïve T cells. SYR treatment induced the expression of Bim as well as activation of FOXO3 in Foxp3 + regulatory T cells (Tregs). Furthermore, SYR treatment significantly enhanced the Firmicutes/Bacteroidetes ratio compared with that in age-matched controls by increasing beneficial bacteria, Lactobacillus and Bifidobacterium, while reducing the opportunistic pathogenic genus, Akkermansia. In addition, SYR treatment reduced the serum level of lipopolysaccharide-binding protein, an inflammatory marker, and enhanced humoral immunity against influenza vaccination to the level of young control mice. Taken together, these findings suggest that SYR may rejuvenate the immune system through modulation of gut integrity and microbiota diversity as well as composition in middle-aged mice, which may delay the immunosenescence associated with aging.

Ulcerative colitis (UC) is associated with a substantial alteration of specific gut commensals, some of which may be involved in microbiota-mediated protection. In this study, microbiota cataloging of UC patients by 16S rRNA microbial profiling revealed a marked reduction of bifidobacteria, in particular the Bifidobacterium bifidum species, thus suggesting that this taxon plays a biological role in the aetiology of UC. We investigated this further through an in vivo trial by testing the effects of oral treatment with B. bifidum PRL2010 in a wild-type murine colitis model. TNBS-treated mice receiving 10(9) cells of B. bifidum PRL2010 showed a marked reduction of all colitis-associated histological indices as well as maintenance of mucosal integrity as it was shown by the increase in the expression of many tight junction-encoding genes. The protective role of B. bifidum PRL2010, as well as its sortase-dependent pili, appears to be established through the induction of an innate immune response of the host. These results highlight the importance of B. bifidum as a microbial biomarker for UC, revealing its role in protection against experimentally induced colitis., (© FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background & Aims: Probiotics is recognized to promote growth performance and immune function via balancing the intestinal microflora. Live clostridium butyricum and bifidobacterium combined powder (LCBBCP) has been widely to treat intestinal dysbacteriosis in newborns in China. This study was undertaken to investigate the effects of the combined probiotics on the expression of B and T lymphocyte attenuator (BTLA) on CD4 + T cells and the differentiation of lymphocyte subsets in late preterm infants., Methods: Eighty eligible late preterm infants were equally randomized into LCBBCP therapy group (oral LCBBCP dissolved in formula milk before intake) and control group (treated with simple formula milk for preterm infants) by random digit table. Flow cytometry was used to determine the expression level of BTLA on CD4 + T cells and the percentage of individual subpopulation of lymphocytes in peripheral-blood mononuclear cells (PBMCs) obtained from the late preterm infants in both groups., Results: BTLA protein expression on CD4 + T cells showed no significant change in LCBBCP therapy group before and after intervention, yet was rapidly and significantly down-regulated in the controls. The percentage of increased CD4 + T cells, decreased CD8 + T cells and increased ratio of CD4 + /CD8 + T cell proportion were seen in both groups after treatment, yet the increasing or decreasing extent in LCBBCP therapy group was more obvious than in control group. The proportion of NK cells and B lymphocytes remained no significant difference between the two groups before and after therapy., Conclusions: LCBBCP appears capable of facilitating the activation, proliferation and differentiation of T lymphocytes, which is beneficial to improving immunity in late preterm infants. The continuous high expression of BTLA on CD4 + T cells in LCBBCP therapy group may be involved in the inhibiting of excessive activation of T lymphocytes. Our findings may lay a basis for further clinical evaluation of the efficacies and wider clinical recommendation of probiotics containing live clostridium butyricum and bifidobacterium for late preterm infants., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Probiotic supplementation to women during pregnancy and lactation can modulate breast milk composition, with immune benefits being transferred to their infants., Aim: The aim of the study was to evaluate the effect of high-dose probiotic supplementation to women during late pregnancy and lactation on cytokine profile and secretory IgA (sIgA) in breast milk and thus to study if differences in breast milk composition can affect lactoferrin and sIgA levels in stool samples of newborns. The safety of maternal probiotic administration on neonatal growth pattern and gastrointestinal symptoms were also evaluated., Methods: In a double-blind, placebo-controlled, randomized trial, 66 women took either the probiotic ( n = 33) or a placebo ( n = 33) daily. Levels of interleukins (IL-6, IL-10 and IL-1β), transforming growth factor-β1 (TGF-β1), and sIgA in breast milk; and the level of sIgA and lactoferrin in newborn stool samples were analyzed at birth and then again at one month of life. Antropometrical evaluation and analysis of gastrointestinal events in newborns was also performed., Results: Probiotic maternal consumption had a significant impact on IL6 mean values in colostrum and on IL10 and TGF-β1 mean values in mature breast milk. Fecal sIgA mean values were higher in newborns whose mothers took the probiotic product than in the control group. Probiotic maternal supplementation seems to decrease incidence of infantile colic and regurgitation in infants., Conclusion: High-dose multi-strain probiotic administration to women during pregnancy influences breast milk cytokines pattern and sIgA production in newborns, and seems to improve gastrointestinal functional symptoms in infants., Competing Interests: The authors declare no conflicts of interest.

Background: Probiotics are "live", beneficial microbes that provide important health benefits in their hosts. There is significant interest in the modulation and regulation of the immune function by probiotics., Objective: To investigate the immunomodulatory effects of a probiotic mixture, including Lactobacillus and Bifidobacterium species, by detecting serum cytokine and immunoglobulin levels., Methods: The rats were randomly divided into 4 groups. The first group was "Control group" and other 3 groups were probiotic application groups who received different doses of probiotics. The probiotic mixture included 12 probiotic bacteria, mostly Lactobacillus and Bifidobacterium strains. Probiotic mixture was administered to rats for 12 consecutive days. TNF-α, TGF-β, IL-1-β, IL-6, and IL-10 levels as well as serum IgG and IgA concentrations were detected in the sera after 12 days., Results: Probiotics led to a decrease in the levels of TNF-α, IL-6 and TGF-β; however, they led to increase in the serum levels of IL-10, IgG and IgA. There were significant differences between control group and probiotic application groups (p<0.05)., Conclusion: These data suggest that the commensal microbiota are important for stimulating both proinflammatory and regulatory responses in order to rapidly clear infections and minimize inflammation-associated tissue damage.

Background: Bacterial contamination of colostrum is common and can decrease IgG absorption in neonatal calves. Strategies that mitigate this situation without complicating colostrum management will benefit dairy calf health and survival., Objectives: To evaluate the effects of supplementing colostrum with oligosaccharides (OS) on serum IgG concentration and apparent efficiency of absorption of IgG (AEA%) in calves fed unpasteurized colostrum and characterize these outcomes with respect to colostrum bacterial exposures., Animals: One hundred twenty-three neonatal dairy calves., Methods: Randomized, blinded, controlled clinical trial conducted at a commercial dairy operation. Calves were enrolled at birth in 1 of 4 treatment groups. Data were complete for 123 calves, which were distributed across the treatment groups as follows: mannan-oligosaccharides (MOS), n = 33; Saccharomyces galacto-oligosaccharides (SGOS), n = 31; Bifidobacterium galacto-oligosaccharides (BGOS), n = 28; and lactose control (CON), n = 31. A commercial radial immunodiffusion kit was used to determine colostrum and serum IgG concentrations. Conventional microbiology methods were used to enumerate colostrum bacterial counts., Results: Bacterial counts were not significantly different among treatment groups. Total bacterial plate counts (TPC) were relatively low for the majority of colostrum samples, but TPC had a significant negative effect on serum IgG concentration and AEA% in the lactose-supplemented control group but not the OS treatment groups., Conclusions and Clinical Importance: These results suggest that a complement of OS structures may mitigate adverse effects of bacteria on transfer of passive immunity (TPI)., (Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Different probiotic strains of Lactobacillus and Bifidobacterium genera possess significant and widely acknowledged health-promoting and immunomodulatory properties. They also provide an affordable means for prevention and treatment of various infectious, allergic and inflammatory conditions as demonstrated in numerous human and animal studies. Despite the ample evidence of protective effects of these probiotics against rotavirus (RV) infection and disease, the precise immune mechanisms of this protection remain largely undefined, because of limited mechanistic research possible in humans and investigated in the majority of animal models. Additionally, while most human clinical probiotic trials are well-standardized using the same strains, uniform dosages, regimens of the probiotic treatments and similar host age, animal studies often lack standardization, have variable experimental designs, and non-uniform and sometime limited selection of experimental variables or observational parameters. This review presents selected data on different probiotic strains of lactobacilli and bifidobacteria and summarizes the knowledge of their immunomodulatory properties and the associated protection against RV disease in diverse host species including neonates., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In this work, we aimed to characterize the antiviral response of an originally established porcine intestinal epithelial cell line (PIE cells) by evaluating the molecular innate immune response to rotavirus (RVs). In addition, we aimed to select immunomodulatory bacteria with antiviral capabilities. PIE cells were inoculated with RVs isolated from different host species and the infective titers and the molecular innate immune response were evaluated. In addition, the protection against RVs infection and the modulation of immune response by different lactic acid bacteria (LAB) strains was studied. The RVs strains OSU (porcine) and UK (bovine) effectively infected PIE cells. Our results also showed that RVs infection in PIE cells triggered TLR3-, RIG-I- and MDA-5-mediated immune responses with activation of IRF3 and NF-κB, induction of IFN-β and up-regulation of the interferon stimulated genes MxA and RNase L. Among the LAB strains tested, Bifidobacterium infantis MCC12 and B. breve MCC1274 significantly reduced RVs titers in infected PIE cells. The beneficial effects of both bifidobacteria were associated with reduction of A20 expression, and improvements of IRF-3 activation, IFN-β production, and MxA and RNase L expressions. These results indicate the value of PIE cells for studying RVs molecular innate immune response in pigs and for the selection of beneficial bacteria with antiviral capabilities.

Klebsiella pneumoniae (Kp) a common cause of pneumonia leads to intense lung injury and mortality that are correlated with infective exacerbations. Probiotics are a class of microorganisms that have immunomodulatory effects to benefit health. We investigated whether the probiotic Bifidobacterium longum 5(1A) induces protection in mice against lung infection induced by Kp and the potential involved mechanisms. Kp infection induced secretion of pro-inflammatory cytokines, neutrophil recruitment, significant bacterial load in the lung and 50% lethality. However, treatment with live B. longum 5(1A) induced faster resolution of inflammation associated with an increased production of IL-10, decreased lung damage with significantly reduction of bacterial burden that contributed to rescue 100% of mice from death. We found that these effects could be attributed, at least in part, to activation of the Toll-like receptor (TLR) adapter protein Mal, since B. longum 5(1A) treatment in Mal-deficient infected mice did not show the protection observed in wild type infected mice. Thus, we propose that live B. longum 5(1A) activates TLR-signaling pathway that results in ROS production and protects the host against pneumonia-induced death by finely tuning the inflammatory response and contributing to faster return to lung homeostasis., (Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)

Prebiotic oligosaccharides, including galacto-oligosaccharides (GOS), are used in infant formula to mimic human milk oligosaccharides, which are known to have an important role in the development of the intestinal microbiota and the immune system in neonates. The maturation of the intestines in piglets closely resembles that of human neonates and infants. Hence, a neonatal piglet model was used to study the multi-faceted effect of dietary GOS in early life. Naturally farrowed piglets were separated from the mother sow 24-48 h postpartum and received a milk replacer with or without the addition of GOS for 3 or 26 d, whereafter several indicators of intestinal colonisation and maturation were measured. Dietary GOS was readily fermented in the colon, leading to a decreased pH, an increase in butyric acid in caecum digesta and an increase in lactobacilli and bifidobacteria numbers at day 26. Histomorphological changes were observed in the intestines of piglets fed a GOS diet for 3 or 26 d. In turn, differences in the intestinal disaccharidase activity were observed between control and GOS-fed piglets. The mRNA expression of various tight junction proteins was up-regulated in the intestines of piglet fed a GOS diet and was not accompanied by an increase in protein expression. GOS also increased defensin porcine β-defensin-2 in the colon and secretory IgA levels in saliva. In conclusion, by applying a neonatal piglet model, it could be demonstrated that a GOS-supplemented milk replacer promotes the balance of the developing intestinal microbiota, improves the intestinal architecture and seems to stimulate the intestinal defence mechanism.

Background: The incidence of food allergies has increased dramatically during the last decade. Recently, probiotics have been studied for the prevention and treatment of allergic disease., Objective: We examined whether Bifidobacterium longum KACC 91563 and Enterococcus faecalis KACC 91532 have the capacity to suppress food allergies., Methods: B longum KACC 91563 and E faecalis KACC 91532 were administered to BALB/c wild-type mice, in which food allergy was induced by using ovalbumin and alum. Food allergy symptoms and various immune responses were assessed., Results: B longum KACC 91563, but not E faecalis KACC 91532, alleviated food allergy symptoms. Extracellular vesicles of B longum KACC 91563 bound specifically to mast cells and induced apoptosis without affecting T-cell immune responses. Furthermore, injection of family 5 extracellular solute-binding protein, a main component of extracellular vesicles, into mice markedly reduced the occurrence of diarrhea in a mouse food allergy model., Conclusion: B longum KACC 91563 induces apoptosis of mast cells specifically and alleviates food allergy symptoms. Accordingly, B longum KACC 91563 and family 5 extracellular solute-binding protein exhibit potential as therapeutic approaches for food allergies., (Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Food allergies can have significant effects on morbidity and on quality of life. Therefore, the development of efficient approaches to reduce the risk of developing food allergies is of considerable interest. The aim of this study was to identify and select probiotic strains with preventive properties against allergies using a combination of in vitro and in vivo approaches. To that end, 31 strains of bifidobacteria and lactic acid bacteria were screened for their immunomodulatory properties in two cellular models, namely, human peripheral blood mononuclear cells (PBMCs) and T helper 2 (Th2)-skewed murine splenocytes. Six strains inducing a high interleukin-10 (IL-10)/IL-12p70 ratio and a low secretion of IL-4 on the two cellular models were selected, and their protective impact was tested in vivo in a murine model of food allergy to β-lactoglobulin. Three strains showed a protective impact on sensitization, with a decrease in allergen-specific IgE, and on allergy, with a decrease in mast cell degranulation. Analysis of the impact of these three strains on the T helper balance revealed different mechanisms of action. The Lactobacillus salivarius LA307 strain proved to block Th1 and Th2 responses, while the Bifidobacterium longum subsp. infantis LA308 strain induced a pro-Th1 profile and the Lactobacillus rhamnosus LA305 strain induced pro-Th1 and regulatory responses. These results demonstrate that a combination of in vitro and in vivo screening is effective in probiotic strain selection and allowed identification of three novel probiotic strains that are active against sensitization in mice., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Toxoplasmosis is frequently acquired through the oral route by the ingestion of cysts or oocysts of Toxoplasma gondii. Once ingested, the parasites penetrate the intestinal epithelial cells and rapidly disseminate to all organs in the host. During T. gondii infection, the intestinal microbiota plays an important role in stimulating a protective immune response against the parasite. In this sense the use of probiotics is worthy of note since they are live microorganisms that have beneficial effects on the host through stimulation of the immune response that can be important in the control of T. gondii proliferation and dissemination in the host. In the present study, the action of the probiotic Bifidobacterium animalis subsp. lactis was investigated in C57BL/6 mice infected with oocysts of ME49 strain of T. gondii. The probiotic had an immunomodulatory action, inducing CD19 lymphocyte proliferation and consequently increasing anti-T. gondii antibody level. Bifidobacterium animalis subsp. lactis provided protection in supplemented mice, compared to the control group. In addition, supplemented animals had milder inflammatory process in the small intestine, indicating that the probiotic protects the intestinal mucosa during infection with T. gondii. It was concluded that the probiotic B. animalis subsp. lactis induces humoral immune response capable of providing protection against T. gondii infection.

Bifidobacterium breve C50 secretes a lipoprotein associated with glucose, acting in an aggregating form (>600kDa) as an agonist of TLR2/6. Similar lipoproteins were sought for in bifidobacteria. In silico, the closest homology was shown with a Bifidobacterium longum protein containing CHAP and lipobox domains. Two strains secreted aggregates whose peptides sequences aligned with the mined protein. C16:0 and C18:0 fatty acids detected in the aggregates further supported a lipoprotein structure. Glucose and mannose detected by gas chromatography were likely ligands of the lipoprotein. The binding of aggregates to galectin-1 indicated that hexosamines and galactose surrounded them. However, unlike B. breve C50, aggregate secreted by B. longum CBi0703 was unable to bind TLR2/6 likely because of a more hydrophobic structure. In gnotobiotic mice, the intake of B. longum aggregate induced, in splenic dendritic cells, the expression of genes involved in antigen presentation. A positive correlation between the number of dendritic cells and CD4(+)CD25(+) cells was observed in mice receiving these aggregates. In conclusion, B. longum secretes a lipoprotein forming aggregates which may influence dendritic and CD4(+)CD25(+) cell interactions independently of the TLR2/6 pathway., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The liver hormone hepcidin is the central regulator of systemic iron metabolism. Its increased expression in inflammatory states leads to hypoferremia and anemia. Elucidation of the mechanisms that up-regulate hepcidin during inflammation is essential for developing rational therapies for this anemia. Using mouse models of inflammatory bowel disease, we have shown previously that colitis-associated hepcidin induction is influenced by intestinal microbiota composition. Here we investigate how two commensal bacteria, Bifidobacterium longum and Bacteroides fragilis, representative members of the gut microbiota, affect hepcidin expression. We found that supernatants of a human macrophage cell line infected with either of the bacteria up-regulated hepcidin when added to a human hepatocyte cell line. This activity was abrogated by neutralization of IL-1β. Moreover, purified IL-1β increased hepcidin expression when added to the hepatocyte line or primary human hepatocytes and when injected into mice. IL-1β activated the bone morphogenetic protein (BMP) signaling pathway in hepatocytes and in mouse liver, as indicated by increased phosphorylation of small mothers against decapentaplegic proteins. Activation of BMP signaling correlated with IL-1β-induced expression of BMP2 in human hepatocytes and activin B in mouse liver. Treatment of hepatocytes with two different chemical inhibitors of BMP signaling or with a neutralizing antibody to BMP2 prevented IL-1β-induced up-regulation of hepcidin. Our results clarify how commensal bacteria affect hepcidin expression and reveal a novel connection between IL-1β and activation of BMP signaling. They also suggest that there may be differences between mice and humans with respect to the mechanism by which IL-1β up-regulates hepcidin., (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)

Gut microbes have ascended to prominence as key modulators of host immunity, raising the possibility that they could influence the outcome of cancer immunotherapy. Two recent studies address this question by identifying specific gut-resident bacteria as drivers of checkpoint blockade immunotherapy in pre-clinical tumor models., (Copyright © 2015 Elsevier Inc. All rights reserved.)

T cell infiltration of solid tumors is associated with favorable patient outcomes, yet the mechanisms underlying variable immune responses between individuals are not well understood. One possible modulator could be the intestinal microbiota. We compared melanoma growth in mice harboring distinct commensal microbiota and observed differences in spontaneous antitumor immunity, which were eliminated upon cohousing or after fecal transfer. Sequencing of the 16S ribosomal RNA identified Bifidobacterium as associated with the antitumor effects. Oral administration of Bifidobacterium alone improved tumor control to the same degree as programmed cell death protein 1 ligand 1 (PD-L1)-specific antibody therapy (checkpoint blockade), and combination treatment nearly abolished tumor outgrowth. Augmented dendritic cell function leading to enhanced CD8(+) T cell priming and accumulation in the tumor microenvironment mediated the effect. Our data suggest that manipulating the microbiota may modulate cancer immunotherapy., (Copyright © 2015, American Association for the Advancement of Science.)

In the review the materials on the formation of intestinal immune homeostasis through involvement of bifidobacteria which are the key species of microbiota of human colon biotype are presented. Key function of dominant microorganisms, bifidoflora in particular, in intestinal biotype of a host is carried out by means of maintenance of self microorganisms and pronounced antagonism concerning non-self. Realization of this principle in intermicrobial relations allowed to develop algorithm of microbial self-non-self discrimination in microsymbiocenosis on the basis of detected opposite phenomenon (enhancement/suppression) of the main physiological functions of microsymbionts survival (reproduction and adaptation) in dominant-associant pair. Primary discrimination of foreign,material by bifidobacteria is the initial stage of the following "signaling" in the regulation of host immune homeostasis. Further stages of regulation occur by activation of dendritic cells by bifidobacteria with the sequential influence on differentiation of Th0 towards regulatory lymphocytes. The formation of Treg and regulation of immune homeostasis are carried out by bifidobacteria: due to direct activation of dendritic cells (ligand-receptor interactions) and maintenance of optimal cytokine balance.

Background: Different delivery modes may affect the susceptibility to allergic diseases. It is still unknown whether early intervention with probiotics would counteract this effect., Objectives: The effect of different delivery modes on immune status and nasal symptoms was investigated on established allergic rhinitis (AR) mouse model. In addition, the immunoregulatory effects and mechanisms of different feeding manners with Bifidobacterium breve(B. breve) were examined., Methods: Live lyophilized B. breve was orally administered to BALB/c mice born via vaginal delivery(VD) or cesarean delivery (CD) for 8 consecutive weeks, after which they were sensitized by ovalbumin(OVA) to establish experimental AR. Nasal symptoms, serum immunoglobulins, cytokines, splenic percentages of CD4(+)CD25(+)Foxp3(+) regulatory T(Treg) cells and nasal eosinophil infiltration were evaluated., Results: Compared with VD mice, mice delivered via CD demonstrated more serious nasal symptoms, higher concentrations of OVA-specific immunoglobulin (Ig) E, more nasal eosinophils and lower percentages of splenic CD4(+)CD25(+)Foxp3(+)Treg cells after establishing experimental AR. These parameters were reversed by administering B. breves hortly after birth. However, the effect of B. breve did not differ between different delivery modes., Conclusion: CD aggravates the nasal symptoms of AR mice compared to VD. This is the first report that oral administration of B. breve shortly after birth can significantly alleviate the symptoms of AR mice born via both deliveries, probably via activation of the regulatory capacity of CD4(+)CD25(+)Foxp3(+)Treg cells.

Background: Bifidobacterium breve M-16V (M16V) is a probiotic bacterial strain with a long tradition of use in neonatal intensive care units in some countries. Previous study showed that the effects of M16V administration on gene expression were greater during the weaning period than in the neonatal period and were greater in the colon than in the small intestine and spleen, suggesting that M16V has anti-inflammatory effects. In this study, we evaluated the effects of inflammation during the weaning period and the effects of M16V on normal and inflammatory conditions., Methods: From postnatal day (PD) 21 to 34, weanling rats were administered of 2.5 × 10(9) of M16V daily, and colitis was induced by administration of 2% dextran sulfate sodium from PD28 to 35. Colitis severity, immune function, and microbiota were investigated., Results: Colitis caused a reduction in body weight gain, colon shortening, poor nutritional status, anemia, changes in blood and spleen lymphocyte populations, spleen T-cell malfunctions, and alterations in colon microbiota. M16V administration improved some but not all of the changes induced by colitis., Conclusion: M16V could suppress inflammation and, therefore, can be considered a safe strain to use not only during the neonatal period but also the weaning period.

Mucin2 (MUC2), an important regulatory factor in the immune system, plays an important role in the host defense system against bacterial translocation. Probiotics known to regulate MUC2 gene expression have been widely studied, but the interactions among probiotic, pathogens, and mucin gene are still not fully understood. The aim of this study was to investigate the role of MUC2 in blocking effects of probiotics on meningitic E. coli-induced pathogenicities. In this study, live combined probiotic tablets containing living Bifidobacterium, Lactobacillus bulgaricus, and Streptococcus thermophilus were used. MUC2 expression was knocked down in Caco-2 cells by RNA interference. 5-Aza-2'-deoxycytidine (5-Aza-CdR), which enhances mucin-promoted probiotic effects through inducing production of Sadenosyl- L-methionine (SAMe), was used to up-regulate MUC2 expression in Caco-2 cells. The adhesion to and invasion of meningitic E. coli were detected by competition assays. Our studies showed that probiotic agents could block E. coli-caused intestinal colonization, bacteremia, and meningitis in a neonatal sepsis and meningitis rat model. MUC2 gene expression in the neonatal rats given probiotic agents was obviously higher than that of the infected and uninfected control groups without probiotic treatment. The prohibitive effects of probiotic agents on MUC2-knockdown Caco-2 cells infected with E44 were significantly reduced compared with nontransfected Caco-2 cells. Moreover, the results also showed that 5- Aza-CdR, a drug enhancing the production of SAMe that is a protective agent of probiotics, was able to significantly suppress adhesion and invasion of E44 to Caco-2 cells by upregulation of MUC2 expression. Taken together, our data suggest that probiotic agents can efficiently block meningitic E. coli-induced pathogenicities in a manner dependent on MUC2.

Aims: This study was designed to demonstrate the protective effects of Bifidobacterium longum BBMN68-specific modulated dendritic cells (DCs) on allergic inflammation in β-lactoglobulin (BLG)-sensitized mice., Methods and Results: BALB/c mice were sensitized to BLG in accordance with a model of food allergy protocol and given oral BBMN68 daily. BBMN68 was found to significantly reduce BLG-specific hypersensitivity reactions by suppressing the aberrant balance of Th1/Th2 responses with increasing the number of CD4+CD25+Foxp3+ Treg cells in mesenteric lymph nodes (MLN) by 48·1%. The level of CD103+DCs was up-regulated by 136·7 and 56·2% in payer's patches and MLN, respectively, in response to the lower expression levels of cell-surface molecules (CD86 and MHC-II) induced by BBMN68 supplementation. The CD11c+DCs isolated from BBMN68 mice showed 45·6% more Foxp3+ expression in vitro., Conclusions: These data suggest that BBMN68-specific induction of CD11c+CD103+DCs and semi-mature DCs reduce BLG allergic reactions., Significance and Impact of the Study: These data confirm that BBMN68 may be a suitable therapeutic approach to the alleviation of food allergies, and BBMN68-specific induction of CD11c+CD103+DCs and semi-mature DCs are associated with this protection., (© 2015 The Society for Applied Microbiology.)

Background: Breastfed human infants are predominantly colonized by bifidobacteria that thrive on human milk oligosaccharides (HMO). Two predominant species of bifidobacteria in infant feces are Bifidobacterium breve (B. breve) and Bifidobacterium longum subsp. infantis (B. infantis), both of which include avid HMO-consumer strains. Our laboratory has previously shown that B. infantis, when grown on HMO, increases adhesion to intestinal cells and increases the expression of the anti-inflammatory cytokine interleukin-10. The purpose of the current study was to investigate the effects of carbon source-glucose, lactose, or HMO-on the ability of B. breve and B. infantis to adhere to and affect the transcription of intestinal epithelial cells on a genome-wide basis., Results: HMO-grown B. infantis had higher percent binding to Caco-2 cell monolayers compared to B. infantis grown on glucose or lactose. B. breve had low adhesive ability regardless of carbon source. Despite differential binding ability, both HMO-grown strains significantly differentially affected the Caco-2 transcriptome compared to their glucose or lactose grown controls. HMO-grown B. breve and B. infantis both downregulated genes in Caco-2 cells associated with chemokine activity., Conclusion: The choice of carbon source affects the interaction of bifidobacteria with intestinal epithelial cells. HMO-grown bifidobacteria reduce markers of inflammation, compared to glucose or lactose-grown bifidobacteria. In the future, the design of preventative or therapeutic probiotic supplements may need to include appropriately chosen prebiotics.

Background/objectives: The role of intestinal dysbiosis in obesity-associated systemic inflammation via the cross-talk with peripheral tissues is under debate. Our objective was to decipher the mechanisms by which intervention in the gut ecosystem with a specific Bifidobacterium strain reduces systemic inflammation and improves metabolic dysfunction in obese high-fat diet (HFD) fed mice., Methods: Adult male wild-type C57BL-6 mice were fed either a standard or HFD, supplemented with placebo or Bifidobacterium pseudocatenulatum CECT 7765, for 14 weeks. Lymphocytes, macrophages and cytokine/chemokine concentrations were quantified in blood, gut, liver and adipose tissue using bead-based multiplex assays. Biochemical parameters in serum were determined by ELISA and enzymatic assays. Histology was assessed by hematoxylin-eosin staining. Microbiota was analyzed by 16S rRNA gene pyrosequencing and quantitative PCR., Results: B. pseudocatenulatum CECT 7765 reduced obesity-associated systemic inflammation by restoring the balance between regulatory T cells (Tregs) and B lymphocytes and reducing pro-inflammatory cytokines of adaptive (IL-17A) and innate (TNF-α) immunity and endotoxemia. In the gut, the bifidobacterial administration partially restored the HFD-induced alterations in microbiota, reducing abundances of Firmicutes and of LPS-producing Proteobacteria, paralleled to reductions in B cells, macrophages, and cytokines (IL-6, MCP-1, TNF-α, IL-17A), which could contribute to systemic effects. In adipose tissue, bifidobacterial administration reduced B cells whereas in liver the treatment increased Tregs and shifted different cytokines (MCP-1 plus ILP-10 in adipose tissue and INF-γ plus IL-1β in liver). In both tissues, the bifidobacteria reduced pro-inflammatory macrophages and, TNF-α and IL-17A concentrations. These effects were accompanied by reductions in body weight gain and in serum cholesterol, triglyceride, glucose and insulin levels and improved oral glucose tolerance and insulin sensitivity in obese mice., Conclusions: Here, we provide evidence of the immune cellular mechanisms by which the inflammatory cascade associated with diet-induced obesity is attenuated by the administration of a specific Bifidobacterium strain and that these effects are associated with modulation of gut microbiota structure.

Aim: Evaluate immune regulatory properties of bifidobacteria metabolites during eubiosis and dysbiosis of the human colon., Materials and Methods: Anti-cytokine activity of metabolites of bifidobacteria clinical strains and their ability to influence the production of pro- and anti-inflammatory cytokines (IL-10) by peripheral blood mononuclear cells of healthy humans was studied, taking into account microecological state of the human intestine. Determination of final concentration of cytokines in experimental and control samples was carried out by EIA., Results: Sensitive parameters, that are suitable for evaluation of stability of human intestine microsymbiocenosis, were detected. The level of microbial seeding, concentration of TNF-α and anti-lysozyme activity turned out to be informative for bifidobacteria in eubiosis conditions. The ability of bifidoflora metabolites to influence the production of pro-inflammatory cytokines (INF-γ, TNF-α, IL-8) by human mononuclears was a significant parameter during formation of 1 - 3 degree dysbiosis., Conclusion: The maintenance of physiological state of intestine homeostasis is determined by immune regulatory properties of bifidobacteria metabolites, that is realized via their interaction with both cytokines (anti-cytokine activity) and production of cytokines by host immune cells (peripheral blood mononuclears).

Probiotic ingestion is recommended as a preventive approach to maintain the balance of the intestinal microbiota and to enhance the human well-being. During the whole life of each individual, the gut microbiota composition could be altered by lifestyle, diet, antibiotic therapies and other stress conditions, which may lead to acute and chronic disorders. Hence, probiotics can be administered for the prevention or treatment of some disorders, including lactose malabsorption, acute diarrhoea, irritable bowel syndrome, necrotizing enterocolitis and mild forms of inflammatory bowel disease. The probiotic-mediated effect is an important issue that needs to be addressed in relation to strain-specific probiotic properties. In this work, the probiotic properties of new Lactobacillus and Bifidobacterium strains were screened, and their effects in vitro were evaluated. They were screened for probiotic properties by determining their tolerance to low pH and to bile salts, antibiotic sensitivity, antimicrobial activity and vitamin B8, B9 and B12 production, and by considering their ability to increase the antioxidant potential and to modulate the inflammatory status of systemic-miming cell lines in vitro. Three out of the examined strains presenting the most performant probiotic properties, as Lactobacillus plantarum PBS067, Lactobacillus rhamnosus PBS070 and Bifidobacterium animalis subsp. lactis PBSO75, were evaluated for their effects also on human intestinal HT-29 cell line. The obtained results support the possibility to move to another level of study, that is, the oral administration of these probiotical strains to patients with acute and chronic gut disorders, by in vivo experiments.

In the article new line of research--infectious symbiology that studies interaction of microsymbionts with the host in case of infection under the conditions of their biocommunicative interrelations is discussed. The presence of interrelation of intestinal microbiota with human homeostasis disorders postulates thesis that: human organism is superorganism including a lot of prokaryote species where microbiota normoflora representatives are the main complex of extra-corporeal physiological system acting as organism homeostasis regulator. When studying intermicrobial relations under microsymbiocenosis its system-forming factor has been identified that includes basic general functions of microorganisms--reproductive (growth/reproduction) and adaptive (biofilm formation and antilysozyme test). It has been shown that microbial interaction in dominant-associant vector providing microsymbiocenosis functioning is implemented via opposite (amplification/suppression) effect of reproductive and adaptive functions of microsymbionts of dominant-associant pair contributing self-non-self discrimination. Intermicrobial discrimination of self-non-self microsymbionts goes before signaling of adaptive immunity of the host promoting microbe elimination or persistence in the body depending on the result of identification. It has been noted that microbial factor fulfilling the role of organism homeostasis regulator performs synergistic functioning of dominant microflora with the host. When penetrating foreign associants (pathogens) into the organism host defense is implemented by means of induction of its adaptive immunity via cytokine reticulum. Key players of human intestinal microbiota are Bifidobacteria which along with induction of adaptive immunity and balance changes of pro- and anti-inflammatory cytokines of the host directly regulate microsymbiocenosis including system of hormones and neurotransmitters.

Background: There is strong evidence to support a genetic predisposition to eczema and more recently studies have suggested that probiotics might be used to prevent eczema by modifying the expression of putative allergy-associated genes. The aim of this present study was to investigate whether two probiotics, Lactobacillus rhamnosus HN001 (HN001) and Bifidobacterium animalis subsp. lactis HN019 (HN019), can modify the known genetic predisposition to eczema conferred by genetic variation in the Toll-like receptor (TLR) genes in a high-risk infant population., Methods: We selected 54 SNPs in the Toll-like receptor genes. These SNPs were analysed in 331 children of sole European ancestry as part of a double-blind, randomized, placebo-controlled trial examining the effects of HN001 and HN019 supplementation on eczema development and atopic sensitization., Results: The data showed that 26 TLR SNPs interacted with HN001 resulting in a significantly reduced risk of eczema, 18 for eczema severity as defined by SCORAD ≥ 10 and 20 for atopic sensitization compared to placebo. There were only two SNPs that interacted with HN019 resulting in a reduced risk of eczema, eczema severity or atopy., Conclusions: This is the first study to show that the negative impact of specific TLR genotypes may be positively affected by probiotic supplementation. HN001 exhibits a much stronger effect than HN019 in this respect., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)