The commensal bacterium Lactiplantibacillus plantarum imprints innate memory-like responses in mononuclear phagocytes.

Gut microbiota is a constant source of antigens and stimuli to which the resident immune system has developed tolerance. However, the mechanisms by which mononuclear phagocytes, specifically monocytes/macrophages, cope with these usually pro-inflammatory signals are poorly understood. Here, we show that innate immune memory promotes anti-inflammatory homeostasis, using as model strains of the commensal bacterium Lactiplantibacillus plantarum. Priming of monocytes/macrophages with bacteria, especially in its live form, enhances bacterial intracellular survival and decreases the release of pro-inflammatory signals to the environment, with lower production of TNF and higher levels of IL-10. Analysis of the transcriptomic landscape of these cells shows downregulation of pathways associated with the production of reactive oxygen species (ROS) and the release of cytokines, chemokines and antimicrobial peptides. Indeed, the induction of ROS prevents memory-induced bacterial survival. In addition, there is a dysregulation in gene expression of several metabolic pathways leading to decreased glycolytic and respiratory rates in memory cells. These data support commensal microbe-specific metabolic changes in innate immune memory cells that might contribute to homeostasis in the gut.

Priming with intranasal lactobacilli prevents Pseudomonas aeruginosa acute pneumonia in mice.

BACKGROUND: Increasing resistance to antibiotics of Pseudomonas aeruginosa leads to therapeutic deadlock and alternative therapies are needed. We aimed to evaluate the effects of Lactobacillus clinical isolates in vivo, through intranasal administration on a murine model of Pseudomonas aeruginosa pneumonia. RESULTS: We screened in vitro 50 pulmonary clinical isolates of Lactobacillus for their ability to decrease the synthesis of two QS dependent-virulence factors (elastase and pyocyanin) produced by Pseudomonas aeruginosa strain PAO1. Two blends of three Lactobacillus isolates were then tested in vivo: one with highly effective anti-PAO1 virulence factors properties (blend named L.rff for L. rhamnosus, two L. fermentum strains), and the second with no properties (blend named L.psb, for L. paracasei, L. salivarius and L. brevis). Each blend was administered intranasally to mice 18 h prior to PAO1 pulmonary infection. Animal survival, bacterial loads, cytological analysis, and cytokines secretion in the lungs were evaluated at 6 or 24 h post infection with PAO1. Intranasal priming with both lactobacilli blends significantly improved 7-day mice survival from 12% for the control PAO1 group to 71 and 100% for the two groups receiving L.rff and L.psb respectively. No mortality was observed for both control groups receiving either L.rff or L.psb. Additionally, the PAO1 lung clearance was significantly enhanced at 24 h. A 2-log and 4-log reduction was observed in the L.rff + PAO1 and L.psb + PAO1 groups respectively, compared to the control PAO1 group. Significant reductions in neutrophil recruitment and proinflammatory cytokine and chemokine secretion were observed after lactobacilli administration compared to saline solution, whereas IL-10 production was increased. CONCLUSIONS: These results demonstrate that intranasal priming with lactobacilli acts as a prophylaxis, and avoids fatal complications caused by Pseudomonas aeruginosa pneumonia in mice. These results were independent of in vitro anti-Pseudomonas aeruginosa activity on QS-dependent virulence factors. Further experiments are required to identify the immune mechanism before initiating clinical trials.

Is bacterial vaginosis associated with autoimmune antibody positivity?

OBJECTIVE: To evaluate the association between bacterial vaginosis (BV) and autoimmune antibody positivity. METHOD: We evaluated Papanicolaou-stained cervicovaginal smears of 210 patients with poor obstetric history who were admitted to a special preconception counselling programme. Cytological specimens with various types of microorganisms except for BV, epithelial cell abnormalities and other non-neoplastic findings, including inflammation were excluded from the cohort in addition to patients with autoimmune and chronic inflammatory diseases. The remaining study population (n = 121) was divided into two groups of patients with autoimmune antibody positivity (study group, n = 80) and patients without antibody positivity (control group, n = 41). RESULTS: The rate of BV was demonstrated to be 13.8% and 2.4% in the study and control groups respectively (P = .042). We also demonstrated that the anti-nuclear antibody was positive in 58.3% of the cases with BV. CONCLUSION: BV was found more frequently in patients with autoimmune antibody positivity to a statistically significant degree.

Specific gut microbiome members are associated with distinct immune markers in pediatric allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Increasing evidence reveals the importance of the microbiome in health and disease and inseparable host-microbial dependencies. Host-microbe interactions are highly relevant in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT), i.e., a replacement of the cellular components of the patients' immune system with that of a foreign donor. HSCT is employed as curative immunotherapy for a number of non-malignant and malignant hematologic conditions, including cancers such as acute lymphoblastic leukemia. The procedure can be accompanied by severe side effects such as infections, acute graft-versus-host disease (aGvHD), and death. Here, we performed a longitudinal analysis of immunological markers, immune reconstitution and gut microbiota composition in relation to clinical outcomes in children undergoing HSCT. Such an analysis could reveal biomarkers, e.g., at the time point prior to HSCT, that in the future could be used to predict which patients are of high risk in relation to side effects and clinical outcomes and guide treatment strategies accordingly. RESULTS: In two multivariate analyses (sparse partial least squares regression and canonical correspondence analysis), we identified three consistent clusters: (1) high concentrations of the antimicrobial peptide human beta-defensin 2 (hBD2) prior to the transplantation in patients with high abundances of Lactobacillaceae, who later developed moderate or severe aGvHD and exhibited high mortality. (2) Rapid reconstitution of NK and B cells in patients with high abundances of obligate anaerobes such as Ruminococcaceae, who developed no or mild aGvHD and exhibited low mortality. (3) High inflammation, indicated by high levels of C-reactive protein, in patients with high abundances of facultative anaerobic bacteria such as Enterobacteriaceae. Furthermore, we observed that antibiotic treatment influenced the bacterial community state. CONCLUSIONS: We identify multivariate associations between specific microbial taxa, host immune markers, immune cell reconstitution, and clinical outcomes in relation to HSCT. Our findings encourage further investigations into establishing longitudinal surveillance of the intestinal microbiome and relevant immune markers, such as hBD2, in HSCT patients. Profiling of the microbiome may prove useful as a prognostic tool that could help identify patients at risk of poor immune reconstitution and adverse outcomes, such as aGvHD and death, upon HSCT, providing actionable information in guiding precision medicine.

Food-Origin Lactic Acid Bacteria May Exhibit Probiotic Properties: Review.

One of the most promising areas of development in the human nutritional field over the last two decades has been the use of probiotics and recognition of their role in human health and disease. Lactic acid-producing bacteria are the most commonly used probiotics in foods. It is well known that probiotics have a number of beneficial health effects in humans and animals. They play an important role in the protection of the host against harmful microorganisms and also strengthen the immune system. Some probiotics have also been found to improve feed digestibility and reduce metabolic disorders. They must be safe, acid and bile tolerant, and able to adhere and colonize the intestinal tract. The means by which probiotic bacteria elicit their health effects are not understood fully, but may include competitive exclusion of enteric pathogens, neutralization of dietary carcinogens, production of antimicrobial metabolites, and modulation of mucosal and systemic immune function. So far, lactic acid bacteria isolated only from the human gastrointestinal tract are recommended by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) for use as probiotics by humans. However, more and more studies suggest that strains considered to be probiotics could be isolated from fermented products of animal origin, as well as from non-dairy fermented products. Traditional fermented products are a rich source of microorganisms, some of which may exhibit probiotic properties. They conform to the FAO/WHO recommendation, with one exception; they have not been isolated from human gastrointestinal tract. In light of extensive new scientific evidence, should the possibility of changing the current FAO/WHO requirements for the definition of probiotic bacteria be considered?

Development of a potential probiotic yoghurt using selected anti-inflammatory lactic acid bacteria for prevention of colitis and carcinogenesis in mice.

AIMS: To evaluate the beneficial properties of a potentially probiotic yoghurt obtained by the fermentation of two selected anti-inflammatory bacterial strains using in vivo mouse models of intestinal inflammation and colon carcinogenesis. METHODS AND RESULTS: Yoghurt was administered to mice suffering chemically induced intestinal inflammation or colon carcinogenesis. It was shown that this novel yoghurt was able to prevent local inflammation in the intestines of mice through a regulation of the immune response, prevent macroscopic and histological damages, and prevent colon carcinogenesis through an anti-inflammatory response. CONCLUSIONS: The developed yoghurt showed in vivo anti-inflammatory properties by modulation of the host immune response for the prevention of colon inflammation and carcinogenesis. SIGNIFICANCE AND IMPACT OF THE STUDY: This new yoghurt could thus be considered a probiotic food and be useful as a complement to current treatment protocols for inflammatory bowel diseases and colon cancer, a first since there are no current functional foods specifically oriented for these patients.

Oral Probiotic VSL#3 Prevents Autoimmune Diabetes by Modulating Microbiota and Promoting Indoleamine 2,3-Dioxygenase-Enriched Tolerogenic Intestinal Environment.

The gut microbiota modulates the autoimmune pathogenesis of type 1 diabetes (T1D) via mechanisms that remain largely unknown. The inflammasome components are innate immune sensors that are highly influenced by the gut environment and play pivotal roles in maintaining intestinal immune homeostasis. In this study we show that modifications of the gut microbiota induced by oral treatment with Lactobacillaceae-enriched probiotic VSL#3, alone or in combination with retinoic acid (RA), protect NOD mice from T1D by affecting inflammasome at the intestinal level. In particular, we show that VSL#3 treatment inhibits IL-1ß expression while enhancing release of protolerogenic components of the inflammasome, such as indoleamine 2,3-dioxygenase (IDO) and IL-33. Those modifications of the intestinal microenvironment in VSL#3-treated NOD mice modulate gut immunity by promoting differentiation of tolerogenic CD103(+) DCs and reducing differentiation/expansion of Th1 and Th17 cells in the intestinal mucosa and at the sites of autoimmunity, that is, within the pancreatic lymph nodes (PLN) of VSL#3-treated NOD mice. Our data provide a link between dietary factors, microbiota composition, intestinal inflammation, and immune homeostasis in autoimmune diabetes and could pave the way for new therapeutic approaches aimed at changing the intestinal microenvironment with probiotics to counterregulate autoimmunity and prevent T1D.

Immunomodulation properties of multi-species fermented milks.

Dairy propionibacteria (PAB) are used as a ripening starter in combination with Lactic acid bacteria (LAB) for dairy products such as Swiss-type cheese. LAB and PAB have also been studied for their probiotic properties but little is still known about their individual and/or synergistic beneficial effects within dairy matrices. In the context of a rising incidence of Inflammatory Bowel Diseases, it has become crucial to evaluate the immunomodulatory potential of bacteria ingested in large numbers via dairy products. We therefore selected different strains and combinations of technological LAB and PAB. We determined their immunomodulatory potential by IL-10 and IL-12 induction, in human peripheral blood mononuclear cells, on either single or mixed cultures, grown on laboratory medium or directly in milk. Milk was fermented with selected anti-inflammatory strains of LAB or PAB/LAB mixed cultures and the resulting bacterial fractions were also evaluated for these properties, together with starter viability and optimum technological aspects. The most promising fermented milks were evaluated in the context of TNBS- or DSS-induced colitis in mice. The improvement in inflammatory parameters evidenced an alleviation of colitis symptoms as a result of fermented milk consumption. This effect was clearly strain-dependent and modulated by growth within a fermented dairy product. These findings offer new tools and perspectives for the development of immunomodulatory fermented dairy products for targeted populations.

Effect of bovine colostrum feeding in comparison with milk replacer and natural feeding on the immune responses and colonisation of enterotoxigenic Escherichia coli in the intestinal tissue of piglets.

The present study investigated the effect of feeding bovine colostrum (BC) to piglets in comparison with feeding a milk replacer (MR) and conventional rearing by the sow on the intestinal immune system and number of enterotoxigenic Escherichia coli (ETEC) colonising the intestinal tissue. Piglets (23-d-old) were allocated to one of the following four groups: (1) killed at the beginning of the experiment (Base); (2) separated from the sow and fed BC (BC-fed); (3) separated from the sow and fed a MR (MR-fed); (4) kept with the sow (Sow-Milk). Blood was sampled on days 1 and 8, and faecal samples were collected on days 1, 3, 5 and 8. On day 8, piglets were killed and gastrointestinal digesta and intestinal segments were collected. The frequency of diarrhoea was found to be higher (P≤ 0·019) in MR-fed piglets than in BC-fed and Sow-Milk piglets. Piglets from the MR-fed group had the lowest lactic acid bacteria:haemolytic E. coli ratio (P(treat)= 0·064) in the faeces. The number of E. coli colonising the intestinal tissue was higher (P< 0·001) in piglets from the MR-fed group than in those from the BC-fed and Sow-Milk groups. Piglets from the Sow-Milk group had a higher (P= 0·020) mucosal IgG concentration than those from the MR-fed group, but did not exhibit any difference when compared with piglets from the Base and BC-fed groups. Piglets from the BC-fed group exhibited a reduced (P≤ 0·037) expression level of Toll-like receptor-4 in the intestinal mucosa when compared with those from the MR-fed and Sow-Milk groups. The expression level of IL-2 was higher (P≤ 0·051) in piglets from the MR-fed group than in those from the other treatment groups. In conclusion, feeding BC rather than MR to the piglets reduced the colonisation of intestine by ETEC and modulated the intestinal immune system, whereas no differences were observed in piglets fed BC and conventionally reared by the sows.

Antiviral potential of lactic acid bacteria and their bacteriocins.

Emerging resistance to antiviral agents is a growing public health concern worldwide as it was reported for respiratory, sexually transmitted and enteric viruses. Therefore, there is a growing demand for new, unconventional antiviral agents which may serve as an alternative to the currently used drugs. Meanwhile, published literature continues shedding the light on the potency of lactic acid bacteria (LAB) and their bacteriocins as antiviral agents. Health-promoting LAB probiotics may exert their antiviral activity by (1) direct probiotic-virus interaction; (2) production of antiviral inhibitory metabolites; and/or (3) via stimulation of the immune system. The aim of this review was to highlight the antiviral activity of LAB and substances they produce with antiviral activity.

Molecular identification of potential Th1/Th2 responses-modulating bacterial genes using suppression subtractive DNA hybridization.

BACKGROUND AND OBJECTIVES: We characterized the immunomodulating potential of a number of lactobacilli isolated from an African fermented food by co-incubation with peripheral blood mononuclear cells (PBMCs). Two strains with different immune modulating properties were genetically compared by suppression subtractive hybridization (SSH). METHODS: From 48 Lactobacillus strains isolated from Kimere, African fermented pearl millet dough, 10 were selected based on their bile salt tolerance. Their effects on secretion by PBMCs of the T-helper cells Th1- and Th2-cytokines IFN-γ and IL-4, respectively, in the presence or absence of staphylococcal enterotoxin A (SEA) were assessed. To study the genetic basis of different immune-modulating properties, a subtracted cDNA library for L. fermentum strains K1-Lb1 (Th1 inducer) and K8-Lb1 (Th1 and Th2 suppressor) was constructed using SSH. Finally, adhesion of these strains to hydrocarbons (relative hydrophobicity) and to human HT-29 colonic epithelial cell line was assessed. RESULTS: Two strains, K1-Lb1 and K4-Lb6, induced basal IFN-γ secretion. Four strains, K1-Lb6, K6-Lb2, K7-Lb1, and K8-Lb1 diminished INF-γ secretion by SEA-stimulated PBMCs. All strains, except K1-Lb1, K2-Lb4, and K9-Lb3, inhibited SEA-stimulated IL-4 secretion. Comparing the genomes of K1-Lb1 and K8-Lb1 by SSH indicated that K1-Lb1 is able to synthetize polysaccharides, for the synthesis of which K1-Lb8 appears to lack enzymes. A difference in the hydrophobicity properties of the surfaces of both strains indicated that this has impact on their surface. CONCLUSION: The K1-Lb1-specific sequences encoding putative glycosyltransferases and enzymes for polysaccharides synthesis may account for the observed differences in immunomodulation and surface properties between the two strains and for mediating potential probiotic effects.

A dried yeast fermentate selectively modulates both the luminal and mucosal gut microbiota and protects against inflammation, as studied in an integrated in vitro approach.

EpiCor, derived from Saccharomyces cerevisiae, has been shown to have immunomodulating properties in human clinical trials and in vitro. However, the underlying mechanisms behind its immune protection via the gut remain largely unknown. Therefore, the aim of this study was to use an integrated in vitro approach to evaluate the metabolism of EpiCor by the intestinal microflora, its modulating effect on the gut microbiota, and its anti-inflammatory activity on human-derived cell lines. Using the SHIME model, in combination with a mucus adhesion assay, has shown that low doses of EpiCor have a prebiotic-like modulatory effect on the luminal- and mucosa-associated microbiota. These include gradual changes in general community structure, reduction of potential pathogens, quantitative increase in lactobacilli, and qualitative modulation of bifidobacteria. Moreover, by combination of the SHIME with Caco-2 cells and Caco-2/THP1 cocultures, a significant decrease in pro-inflammatory cytokines was observed at the end of the treatment period.

[Teichoic acids from lactic acid bacteria].

The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

Alteration of the murine gut microbiota during infection with the parasitic helminth Heligmosomoides polygyrus.

BACKGROUND: In a murine model of inflammatory bowel disease (IBD), treatment of colitis in IL-10 gene-deficient mice with the parasitic helminth Heligmosomoides polygyrus ameliorates colonic inflammation. The cellular and molecular mechanisms driving this therapeutic host response are being studied vigorously. One proposed mechanism is that H. polygyrus infection favors the outgrowth or suppression of certain bacteria, which in turn help modulate host immunity. METHODS: To quantify the effect of H. polygyrus infection on the composition of the gastrointestinal (GI) tract microbiota, we conducted two independent microbial ecology analyses of C57BL/6 mice. We obtained and analyzed 3,353 bacterial 16S rRNA encoding gene sequences from the ileum and cecum of infected and uninfected mice as well as incective H. polygyrus larvae at the outset of the second experiment and adult worms taken directly from the mouse duodenum at the end of the second experiment. RESULTS: We found that a significant shift in the abundance and relative distribution of bacterial species in the ileum of mice is associated with H. polygyrus infection. Members of the bacterial family Lactobacillaceae significantly increased in abundance in the ileum of infected mice reproducibly in two independent experiments despite having different microbiotas present at the outset of each experiment. CONCLUSIONS: These data support the concept that helminth infection shifts the composition of intestinal bacteria. The clinical consequences of these shifts in intestinal flora are yet to be explored.

[Neutrophil extracellular traps: method of detection and assessment of bacterial trapping efficacy].

AIM: To develop express method for detection of neutrophil extracellular traps represented by extracellular strands of neutrophils' DNA. MATERIALS AND METHODS: Acridine orange staining was used for visualization of neutrophil exracellular traps, which allows to quickly reveal the forming structures and to quantify this phenomenon. RESULTS: Performed studies showed that after 30-min of in vitro interaction of Escherichia coli, Staphylococcus aureus, lactobacteria, bifidobacteria and latex particles with neutrophils, the latter produces extracellular net-like structures, which were well visualized after staining of fixed preparations with acridine orange. Such structures are able to trap latex particles and bacteria more efficiently than live cell. Additionally, representatives of normal flora (bifidobacteria) actively stimulate production of traps. CONCLUSION: Production of neutrophil extracellular traps could be one of the main and effective mechanisms in antimicrobial defense of mucosal surfaces.

Bacteriocins from lactic acid bacteria increases tumor necrosis factor-alpha expression in a rat kidney model of chronic rejection.

Chronic allograft dysfunction is the primary cause of graft loss after the first posttransplantation year. Bacteriocins are biologically active proteins exhibiting antimicrobial properties against other bacterial species, which are usually closely related to the producer organism. The objective of our study was to determine whether lactic acid bacterial bacteriocins were associated with tumor necrosis factor (TNF)-alpha observed in a rat kidney model of chronic rejection. Using a kidney model of chronic rejection in the rat, we administered cyclosporine (CsA) immunosuppression (5 mg/kg/d). One group of animals was treated with bacteriocins, and the other was left untreated. Grafts were harvested after transplantation for standard histological studies. The expression of TNF-alpha was demonstrated using immunohistochemistry of frozen sections of the grafts. We observed a greater increase in the expression of TNF-alpha among the group treated with bacteriocins compared with the untreated group. These results showed that lactic acid bacterial bacteriocins were associated with TNF-alpha in our kidney graft model.

Antiinflammatory effect of lactic acid bacteria: inhibition of cyclooxygenase-2 by suppressing nuclear factor-kappaB in Raw264.7 macrophage cells.

Lactobacillus casei 3260 (L. casei 3260) was evaluated in relation to the inflammatory response mediated by lipopolysaccharide (LPS)-induced nuclear factor-kappaB (NF-kappaB) and cyclooxygenase-2 (COX-2) expression in Raw264.7 macrophage cells. The treatment of Raw264.7 cells with L. casei 3260 significantly inhibited the secretion of tumor necrosis factor-alpha (TNF-alpha) and prostaglandins E2 (PGE2), followed by suppression of COX-2. To clarify the molecular mechanism, the inhibitory effect of L. casei 3260 on the NF-kappaB signaling pathway was examined based on the luciferase reporter activity. Although the treatment of Raw264.7 cells with L. casei 3260 did not affect the transcriptional activity of NF-kappaB, it did inhibit NF-kappaB activation, as determined by the cytosolic p65 release and degradation of I-kappaBalpha. Therefore, these findings suggest that the suppression of COX-2 through inhibiting the NF-kappaB activation by LPS may be associated with the antiinflammatory effects of L. casei 3260 on Raw264.7 cells.

Nuclear magnetic resonance solution structure of PisI, a group B immunity protein that provides protection against the type IIa bacteriocin piscicolin 126, PisA.

Lactic acid bacteria produce and secrete bacteriocins. These bacteriocins are potent antimicrobial peptides that are active against other closely related bacteria. As a means of self-protection, producer organisms also express immunity proteins. Immunity proteins are generally located on the same genetic locus and are cotranscribed with the bacteriocin. Although some cross immunity between bacteriocins has been observed, immunity proteins are typically highly specific. Immunity proteins for the type IIa bacteriocins range from 81 to 115 amino acids in length and display substantial variation in their sequences. Nonetheless, such immunity proteins have been classified into three groupings (groups A, B, and C) according to sequence homology. The structures of a group C (ImB2) and two group A (EntA-im and PedB) immunity proteins have previously been reported. We herein report the nuclear magnetic resonance solution structure of the remaining class of the type IIa immunity proteins. PisI, a 98-amino acid protein, is a group B immunity protein conferring immunity against piscicolin 126 (PisA). Like ImB2, EntA-im, and PedB, PisI folds into a globular protein in aqueous solution and contains an antiparallel four-helix bundle. Compared to ImB2 and EntA-im, PisI has a substantially longer and more flexible N-terminus, but a shorter C-terminus. No direct interaction between the bacteriocin and immunity protein is observed by NMR in either aqueous or membrane mimicking environments. This further suggests that the mechanism that mediates immunity is not due to a direct bacteriocin-immunity protein interaction but rather is receptor-mediated. It has now been confirmed that the four-helix bundle is indeed a structural motif among the type IIa immunity proteins.

In vitro Th1 cytokine-independent Th2 suppressive effects of bifidobacteria.

A comparison between 17 strains of lactic acid bacteria and 15 strains of bifidobacteria indicated that bifidobacteria induced significantly lower levels of interleukin-12 (IL-12) in murine splenic cells. The present study aims to evaluate the effect and mechanism of Bifidobacterium longum BB536, a probiotic strain, in suppressing antigen-induced Th2 immune response in vitro. BB536 suppressed immunoglobulin (Ig) E and IL-4 production by ovalbumin-sensitized splenic cells, but induction of Th1-inducing cytokine production, such as IL-12 and gamma interferon (IFN-gamma) tended to be lower compared with lactic acid bacteria. Neutralization with antibodies to IL-12, IFN-gamma, IL-10 and transforming growth factor beta indicated negative involvement of Th1-inducing cytokines and regulatory cytokines in the suppression of Th2 immune response by BB536, especially when treated at higher doses of BB536 (>10 microg cells/ml). Furthermore, BB536 induced the maturation of immature bone marrow-derived dendritic cells (BM-DCs), and suppressed antigen-induced IL-4 production mediated by BM-DCs. These results suggested that BB536 suppressed Th2 immune responses, partially independent of Th1-inducing cytokines and independent of regulatory cytokines, mediated by antigen-presenting cells such as dendritic cells.

Generation and utilization of polyclonal antibodies to a synthetic C-terminal amino acid fragment of divercin V41, a class IIa bacteriocin.

Polyclonal antibodies have been generated by immunization of rabbits with a chemically synthesized C-terminal part of divercin V41 (DvnCt) conjugated to the carrier protein keyhole limpet hemocyanin (KLH). The sensitivity and reactivity of the DvnCt-KLH-generated antibodies were evaluated by enzyme-linked immunosorbent assay (ELISA) using supernatant from cultures of 13 representative lactic acid bacterium strains, and specificity was confirmed by Western blot analysis. Anti-DvnCt-KLH antibodies were able to recognize not only divercin V41 but also enterocin P and piscicocin V1b, two other members of the class IIa bacteriocins. Production and activity of DvnV41 were evaluated by ELISA and activity tests during the growth of Carnobacterium divergens V41 in MRS medium containing or not containing Tween 80. Divercin V41, enterocin P, and piscicocin V1b were therefore purified by a single-step immunoaffinity chromatography method using a Sepharose matrix CNBr-activated directed binding of anti-DvnCt-KLH polyclonal antibodies.