Oral administration of liveLactococcus lactisC59 suppresses IgE antibody production in ovalbumin-sensitized mice via the regulation of interleukin-4 production

Immunomodulatory action of Lactococcuslactis

Fermented foods are gaining popularity due to health-promoting properties with high levels of nutrients, phytochemicals, bioactive compounds, and probiotic microorganisms. Due to its unique fermentation process, Lactococcus lactis plays a key role in the food business, notably in the manufacturing of dairy products. The superior biological activities of L. lactis in these functional foods include anti-inflammatory and immunomodulatory capabilities. L. lactis boosted growth performance, controlled amino acid profiles, intestinal immunology, and microbiota. Besides that, the administration of L. lactis increased the rate of infection clearance. Innate and acquired immune responses would be upregulated in both local and systemic compartments, resulting in these consequences. L. lactis is often employed in the food sector and is currently being exploited as a delivery vehicle for biological research. These bacteria are being eyed as potential candidates for biotechnological applications. With this in mind, we reviewed the immunomodulatory effects of different L. lactis strains.

Lactococcus lactis NZ9000 Prevents Asthmatic Airway Inflammation and Remodelling in Rats through the Improvement of Intestinal Barrier Function and Systemic TGF-β Production

INTRODUCTION

The use of probiotics has been broadly popularized due to positive effects in the attenuation of aberrant immune responses such as asthma. Allergic asthma is a chronic respiratory disease characterized by airway inflammation and remodelling.

OBJECTIVE

This study was aimed to evaluate the effect of oral administration of Lactococcus lactis NZ9000 on asthmatic airway inflammation and lung tissue remodelling in rats and its relation to the maintenance of an adequate intestinal barrier.

METHODS

Wistar rats were ovalbumin (OVA) sensitized and challenged and orally treated with L. lactis. Lung inflammatory infiltrates and cytokines were measured, and remodelling was evaluated. Serum OVA-specific immunoglobulin (Ig) E levels were assessed. We also evaluated changes on intestinal environment and on systemic immune response.

RESULTS

L. lactis diminished the infiltration of proinflammatory leucocytes, mainly eosinophils, in the bronchoalveolar compartment, decreased lung IL-4 and IL-5 expression, and reduced the level of serum allergen-specific IgE. Furthermore, L. lactis prevented eosinophil influx, collagen deposition, and goblet cell hyperplasia in lung tissue. In the intestine, L. lactis-treated asthmatic rats increased Peyer's patch and goblet cell quantity and mRNA expression of IgA, MUC-2, and claudin. Additionally, intestinal morphological alterations were normalized by L. lactis administration. Splenocyte proliferative response to OVA was abolished, and serum levels of transforming growth factor (TGF)-β were increased by L. lactis treatment.

CONCLUSIONS

These findings suggest that L. lactis is a potential candidate for asthma prevention, and the effect is mediated by the improvement of intestinal barrier function and systemic TGF-β production.

Cream Cheese-Derived Lactococcus chungangensis CAU 28 Modulates the Gut Microbiota and Alleviates Atopic Dermatitis in BALB/c Mice

Atopic dermatitis (AD) has a drastic impact on human health owing to complex skin, gut microbiota, and immune responses. Some lactic acid bacteria (LAB) are effective in ameliorating AD; however, the alleviative effects of dairy products derived from these LAB remain unclear. In this study, the efficacies of Lactococcus chungangensis CAU 28 (CAU 28) cream cheese and L. chungangensis CAU 28 dry cells were evaluated for treating AD in an AD mouse model. Overall, CAU 28 cream cheese administration was more effective against AD than L. chungangensis CAU 28 dry cells. Faeces from CAU 28 cream cheese-administered mice had increased short chain fatty acid, butyrate, acetate, and lactic acid levels, as well as butyrate-producing bacteria, including Akkermansia, Bacteroides, Lactobacillus, and Ruminococcus. Furthermore, oral CAU 28 cream cheese administration resulted in regulatory T cell (Treg)-mediated suppression of T helper type 2 (Th2) immune responses in serum and mRNA expression levels in the ileum. Oral CAU 28 cream cheese further reduced IgE levels, in addition to eosinophil and mast cell numbers. Therefore, CAU 28 cream cheese administration induced a coordinated immune response involving short-chain fatty acids and gut microbiota, indicating its potential for use as a supplement for AD mitigation.

New lactic acid bacteria for skin health via oral intake of heat-killed or live cells

Lactic acid bacteria play an essential role in the food industry in the manufacture of many fermented products (cheese, yogurt, fermented vegetables, etc.). Application of these organisms is now being extended to the area of health improvement, as their probiotic activities become known. Probiotics are defined as viable microorganisms that exert a beneficial effect on the health of the host when they are ingested in sufficient quantity. Lactic acid bacteria and bifidobacteria isolated from the human intestine are the most common probiotics used for human consumption. The development of new probiotics with new beneficial effects is eagerly awaited in the food industry. This review introduces Lactococcus, which are one of the genera of lactic acid bacteria and are mainly isolated from dairy products and fermented vegetables, as new probiotics, focusing especially on Lactococcus lactis H61, which improves skin status in Japanese women with oral intake of heat‐killed or live cells. The deduced mechanisms associated with the beneficial effects of strain H61 are also discussed.

The distinct effects of orally administered Lactobacillus rhamnosus GG and Lactococcus lactis subsp. lactis C59 on gene expression in the murine small intestine

The molecular mechanisms of strain-specific probiotic effects and the impact of the oral administration of probiotic strains on the host’s gene expression are not yet well understood. The aim of this study was to investigate the strain-specific effects of probiotic strain intake on gene expression in the murine small intestine. Two distinct strains of lactic acid bacteria, Lactobacillus rhamnosus GG (GG) and Lactococcus lactis subsp. lactis C59 (C59), were orally administered to BALB/c mice, daily for 2 weeks. The total RNA was isolated from the upper (including the duodenum) and lower (the terminal ileum) small intestine, and gene expression was assessed by microarray analysis. The data revealed (1) oral administration of C59 and GG markedly down-regulated the expression of genes encoding fibrinogen subunits and plasminogen in the upper small intestine; (2) administration of more than 1 × 10⁷ CFU/day of GG changed the gene expression of the host ileum. (3) strain- and dose-related effects on various GO biological processes; and (4) enrichment for B cell-related Gene Ontology terms among up-regulated genes in the terminal ileum of mice administered the 1 × 10⁹ CFU/day of GG. The distinct effects of GG and C59 on gene expression in the intact small intestine provide clues to understand how the health beneficial effects of specific strains of probiotic bacteria are mediated by interactions with intestinal cells.

Enhancement of Oral Tolerance Induction in DO11.10 Mice by Lactobacillus gasseri OLL2809 via Increase of Effector Regulatory T Cells

Food allergy is a serious problem for infants and young children. Induction of antigen-specific oral tolerance is one therapeutic strategy. Enhancement of oral tolerance induction by diet is a promising strategy to prevent food allergy in infants. Thus, in this study, we evaluate the effect of probiotic Lactobacillus gasseri OLL2809 (LG2809) on oral tolerance induction in a mouse model. The degree of oral tolerance induction was evaluated by measuring the proliferation and level of IL-2 production of splenic CD4⁺ T cells from DO11.10 mice fed ovalbumin (OVA) alone or OVA with LG2809. Oral administration of LG2809 significantly decreased the rate of proliferation and IL-2 production by CD4⁺ T cells from OVA-fed mice. LG2809 increased a ratio of CD4⁺ T-cell population, producing high levels of IL-10 and having strong suppressive activity. Moreover, LG2809 increased a ratio of plasmacytoid dendritic cells (pDCs) among the lamina propria (LP) in small intestine. When used as antigen presenting cells to naïve CD4⁺ T cells from DO11.10 mice, LP cells from BALB/c mice fed LG2809 induced higher IL-10 production and stronger suppressive activity than those from non-treated mice. These results suggest that oral administration of LG2809 increases the population of pDCs in the LP, resulting in the enhancement of oral tolerance induction by increasing the ratio of effector regulatory T cells. LG2809 could, therefore, act as a potent immunomodulator to prevent food allergies by promoting oral tolerance.

Daikenchuto (TU-100) shapes gut microbiota architecture and increases the production of ginsenoside metabolite compound K

Many pharmaceutical agents not only require microbial metabolism for increased bioavailability and bioactivity, but also have direct effects on gut microbial assemblage and function. We examined the possibility that these actions are not mutually exclusive and may be mutually reinforcing in ways that enhance long‐term of these agents. Daikenchuto, TU‐100, is a traditional Japanese medicine containing ginseng. Conversion of the ginsenoside Rb1 (Rb1) to bioactive compound K (CK) requires bacterial metabolism. Diet‐incorporated TU‐100 was administered to mice over a period of several weeks. T‐RFLP and 454 pyrosequencing were performed to analyze the time‐dependent effects on fecal microbial membership. Fecal microbial capacity to metabolize Rb1 to CK was measured by adding TU‐100 or ginseng to stool samples to assess the generation of bioactive metabolites. Levels of metabolized TU‐100 components in plasma and in stool samples were measured by LC‐MS/MS. Cecal and stool short‐chain fatty acids were measured by GC‐MS. Dietary administration of TU‐100 for 28 days altered the gut microbiota, increasing several bacteria genera including members of Clostridia and Lactococcus lactis. Progressive capacity of microbiota to convert Rb1 to CK was observed over the 28 days administration of dietary TU‐100. Concomitantly with these changes, increases in all SCFA were observed in cecal contents and in acetate and butyrate content of the stool. Chronic consumption of dietary TU‐100 promotes changes in gut microbiota enhancing metabolic capacity of TU‐100 and increased bioavailability. We believe these findings have broad implications in optimizing the efficacy of natural compounds that depend on microbial bioconversion in general.

Previous Ingestion of Lactococcus lactis by Ethanol-Treated Mice Preserves Antigen Presentation Hierarchy in the Gut and Oral Tolerance Susceptibility

BACKGROUND

Ethanol (EtOH) consumption is able to disturb the ovalbumin (OVA)-oral tolerance induction by interfering on the function of antigen presenting cells (APC), down-regulating dendritic cells (DCs) and macrophages and up-regulating B-lymphocytes and their function, which results in an overall allergic-type immune status. In this study, the potential of a priori administration of Lactococcus lactis (LL) in avoiding loss of oral tolerance in EtOH-treated mice was investigated.

METHODS

Female C57BL/6 mice received, by oral route, ad libitum wild-type (WT) LL or heat-shock protein producer (Hsp65) LL for 4 consecutive days. Seven days later, mice were submitted to short-term high-dose EtOH treatment. After 24 hours, stomach, intestine, spleen, mesenteric lymph nodes (mLN) specimens were collected for biomarkers analysis. Following EtOH-treatment protocol, a group of animals underwent single-gavage OVA-tolerance protocol and sera samples collected for antibody analysis.

RESULTS

The ingestion of WT LL or Hsp65 LL is able to restore oral tolerance to OVA in EtOH-treated mice, by reducing local and systemic allergic outcomes such as gastric mast cells and gut-interleukin-4, as well as serum IgE. WT LL treatment prevents the decrease of mLN regulatory T cells induced by the EtOH treatment. Moreover, LL treatment preserves APC hierarchy and antigen presentation commitment in EtOH-treated mice, with conserved DC and macrophage activity over B lymphocytes in mLN and preserved macrophage activity over DC and B-cell subsets in the spleen.

CONCLUSIONS

The present findings suggest that a priori ingestion of LL preserves essential mechanisms associated with oral tolerance induction that are disturbed by EtOH ingestion. Maintenance of mucosal homeostasis by preserving APC hierarchy and antigen presentation commitment could be associated with T-regulatory subset activities in the gastrointestinal tract.

Novel exopolysaccharides produced by Lactococcus lactis subsp. lactis, and the diversity of epsE genes in the exopolysaccharide biosynthesis gene clusters

To characterize novel variations of exopolysaccharides (EPSs) produced by dairy strains of Lactococcus lactis subsp. lactis and subsp. cremoris, the EPSs of five dairy strains of L. lactis were purified. Sugar composition analysis showed two novel EPSs produced by strains of L. lactis subsp. lactis. One strain produced EPS lacking galactose, and the other produced EPS containing fucose. Among the eps gene clusters of these strains, the highly conserved epsD and its neighboring epsE were sequenced. Sequence and PCR analysis revealed that epsE genes were strain-specific. By Southern blot analysis using epsD, the eps gene cluster in each strain was found to locate to the chromosome or a very large plasmid. This is the first report on the identification of two novel EPSs in L. lactis subsp. lactis. The strains can be detected among other strains by using epsE genes specific to them.

Immunomodulatory Activity of Lactococcus lactis A17 from Taiwan Fermented Cabbage in OVA-Sensitized BALB/c Mice

From fermented Taiwan foods, we have isolated numerous lactic acid bacteria (LAB) of plant origin and investigated their biological activities. This study aimed to investigate the immunomodulatory effect and mechanism of Lactococcus lactis A17 (A17), isolated from Taiwan fermented cabbage, on ovalbumin (OVA)-sensitized mice. Human peripheral blood mononuclear cells were used to verify immune responses of A17 by IFN-γ production. Live (A17-A) and heat-killed A17 (A17-H) were orally administered to OVA-sensitized BALB/c mice to investigate their effects on immunoglobulin (Ig) and cytokine production. The mRNA expression of Toll-like receptors (TLR) and nucleotide binding oligomerization domain (NOD)-like protein receptors in spleen cells was analyzed by real-time RT-PCR. Both live and heat-killed A17 modulate OVA-induced allergic effects. B-cell response was modulated by diminishing IgE production and raising OVA-specific IgG2a production, while T-cell response was modulated by increasing IFN-γ production and decreasing IL-4 production. The mRNA expression of NOD-1, NOD-2, and TLR-4 was down-regulated by A17 as well. This is the first report to describe a naïve Lactococcus lactis A17 strain as a promising candidate for prophylactic and therapeutic treatments of allergic diseases via oral administration. Our results suggest the ameliorative effects of A17 may be caused by modulating NOD-1 NOD-2, and TLR-4 expression.

The interplay between diet and emerging allergy: what can we learn from Indigenous Australians?

The pathophysiology of atopic diseases, including asthma and allergy, is the result of complex gene-environment interactions. Since European colonization the Indigenous population of Australia has undergone significant changes with respect to their lifestyle as hunter-gatherers. These changes have had a detrimental effect on Aboriginal health, in part due to immunological modification. This review provides a comparative look at both the traditional Aboriginal/Indigenous diet and modern Western diets, examines some common allergies increasingly reported in contemporary Indigenous populations, and reviews concepts such the effect of vitamin deficiencies and changes in gut microbiota on immune function.

IgE and chemotherapy

The nexus of chemotherapeutic intervention and the immunomodulation of IgE-related phenomena are not well understood. The relationship bears importance in better understanding the causal and/or resultant effects of one on the other and their collective role in the management and sequelae of the cancer patient. This review discusses the relationship of chemotherapy on immunoglobulins with a focus on IgE and other related biological processes including hypersensitivity reactions and proposes models toward effective management of the cancer patient in this regard.

An intravenous exposure mouse model for prediction of potential drug-sensitization using reporter antigens popliteal lymph node assay

Immune-mediated drug hypersensitivity is a particularly concerning health-safety issue among clinicians given its unpredictability and potentially life-threatening effects, especially with exposure to intravenous drugs. Therefore, the development of intravenous drug-exposure models for drug-hazard assessments has garnered increasing interest in recent years. In this study, we used reporter antigens popliteal lymph node assay to investigate the potential value of intravenous exposure to a selected variety of allergenic compounds, including ovalbumin (OVA), concanavalin A (ConA) and diclofenac. The trinitrophenyl (TNP)-specific antibody-forming cells were used to assess the systemic immune responses to a bystander antigen. Mice were subsequently sensitized by TNP-OVA, and then intravenous exposure to one of the selective compounds. As expected, all positive compounds induced significant popliteal lymph node (PLN) proliferation compared with the control. OVA significantly increased Cluster of Differentiation 4 receptors (CD⁴)⁺ interleukin-4 (IL-4)⁺ T-helper 2 (Th2) cells and, consequently, increased the ratios of IL-4/interferon-γ (IFN-γ) antibody-forming cells (AFCs) in PLNs, while bringing about a dose-dependent increase in immunoglobulin G1 (IgG1) AFCs; these findings indicate that a Th2 hypersensitivity response was induced. A Th2 response was also observed in diclofenac sodium-treated groups, and for ConA, a more mixed Th1/Th2 immune response appeared to be induced. In addition, there was no marked reaction with the negative compound. Together, it seems likely that the intravenous exposure model may be useful for drug-induced systemic hypersensitivity assessments.

Lactobacillus gasseri OLL2809 and its RNA suppress proliferation of CD4(+) T cells through a MyD88-dependent signalling pathway

Recent studies have shown that probiotics are beneficial in prevention and improvement of inflammatory diseases. Accumulating evidence indicates that probiotics can modulate immune cell responses, although the specific molecular mechanism by which probiotics work remains elusive. Because T cells express receptors for microbial components, we examined whether the probiotic strain Lactobacillus gasseri OLL2809 (LG2809) and its components regulate murine CD4(+) T-cell activation. LG2809, as well as two other Lactobacillus strains, inhibited proliferation of CD4(+) T cells; LG2809 had the strongest suppressive activity among them. RNA isolated from LG2809 was also shown to have suppressive activity. We observed this suppressive effect in the culture of CD4(+) T cells stimulated with anti-CD3/CD28 treatment, suggesting a direct effect on CD4(+) T cells. In contrast, the suppressive effect was not observed for CD4(+) T cells from myeloid differentiation primary response gene 88 (MyD88) protein-deficient mice, and was abrogated in the presence of an anti-oxidant reagent, N-acetyl-cysteine (NAC). These results demonstrate that the suppressive effect of LG2809 and its RNA occurred through a MyD88-dependent signalling pathway and suggest involvement of a reactive oxygen species-dependent mechanism. LG2809 RNA injected subcutaneously suppressed delayed-type-hypersensitivity response in DO11.10 mice, and the suppression was abrogated by treatment with NAC. Collectively, these results suggest that suppression of T-cell proliferation by RNA may be one of the mechanisms when a probiotic bacterial strain exerts suppressive effects on inflammatory responses.