Bifidobacterium infantis Potentially Alleviates Shrimp Tropomyosin-Induced Allergy by Tolerogenic Dendritic Cell-Dependent Induction of Regulatory T Cells and Alterations in Gut Microbiota

Chitosan Oligosaccharide Exerts Anti-Allergic Effect against Shrimp Tropomyosin-Induced Food Allergy by Affecting Th1 and Th2 Cytokines

BACKGROUND

Shrimp-derived allergen has a serious impact on people's health. Chitosan oligosaccharide (COS) has anti-allergic action but its function on shrimp allergen-induced allergy and related molecular mechanisms remain unclear.

METHODS

COS and its degrees of polymerization (DP) were selected to interact with shrimp tropomyosin (TM) and IgE was measured. A mouse model of food allergy was established by receiving shrimp TM intraperitoneally. The models were treated with different concentrations of COS. Fecal and serum histamine, serum IgE, IgG1 and IgG2a, and inflammatory cytokines were measured.

RESULTS

The main products for COS were DP2-6 with the contents of 6, 40, 26, 16, and 4%, respectively, and reacted with shrimp TM increasingly when COS DP was increased. Severe symptoms of food allergy were observed in the TM group (diarrhea, anaphylactic response, and rectal temperature). In contrast, COS treatment improved these symptoms significantly (p < 0.05). The sensitized mice were desensitized after they were treated with 1 mg/kg COS. COS treatment significantly reduced serum IgE and IgG1 levels, and increased IgG2a levels (p < 0.05). COS consumption decreased fecal and serum histamine. COS treatment reduced Th2 cytokine (IL-4, IL-5, and IL-13) levels and increased the Th1 cytokine (IFN-γ) level (p < 0.05).

CONCLUSIONS

COS showed anti-allergy properties by regulating the levels of Th1 and Th2 cytokines.

Prophylactic effects of probiotic Bifidobacterium spp. in the resolution of inflammation in arthritic rats

In the present study, the modulatory effects of bifidobacterial spp. (Bifidobacterium breve NCIM 5671, Bifidobacterium longum NCIM 5672 and Bifidobacterium bifidum NCIM 5697) on adjuvant induced arthritis in rats were evaluated. Arthritis was induced in male Wistar rats by injecting 250 μg of Freund's adjuvant directly into the paw. Fifteen days before and 15 days after the induction of arthritis, suspended cultures of bifidobacteria (10⁹ cfu/ml) were administered by oral gavage. Paw volume, bone mineral content, oxidative stress markers, antioxidant enzymes, cytokines, eicosanoids and expression of COX2, as well as bone hydrolytic enzymes, were assessed by RT PCR. Although piroxicam-treated groups (drug control) had better effects than bifidobacteria-treated groups, bifidobacteria probiotics administration exhibited significant (P < 0.05) prophylactic effects in terms of downregulating arthritis markers. Parameters including paw volume, bone mineral content, cytokines, and eicosanoids level were significantly (p < 0.05) modulated in bifidobacteria administered groups compared to arthritic control group. Among the three strains tested, B. breve NCIM 5671 exhibited superior prophylactic effects as assessed in the experimental rat model of arthritis. In conclusion, bifidobacteria probiotics administration can downregulate the markers of arthritis and hence can be a potential therapeutic regimen in the treatment of arthritis.

Cutting Edge: Probiotics and Fecal Microbiota Transplantation in Immunomodulation

Probiotics are commensal or nonpathogenic microbes that confer beneficial effects on the host through several mechanisms such as competitive exclusion, antibacterial effects, and modulation of immune responses. Some probiotics have been found to regulate immune responses via immune regulatory mechanisms. T regulatory (Treg) cells, T helper cell balances, dendritic cells, macrophages, B cells, and natural killer (NK) cells can be considered as the most determinant dysregulated mediators in immunomodulatory status. Recently, fecal microbiota transplantation (FMT) has been defined as the transfer of distal gut microbial communities from a healthy individual to a patient's intestinal tract to cure some immune disorders (mainly inflammatory bowel diseases). The aim of this review was followed through the recent literature survey on immunomodulatory effects and mechanisms of probiotics and FMT and also efficacy and safety of probiotics and FMT in clinical trials and applications.

Newly identified T cell subsets in mechanistic studies of food immunotherapy

Allergen-specific immunotherapy has shown promise for the treatment of food allergy and is currently being evaluated in clinical trials. Although immunotherapy can induce desensitization, the mechanisms underlying this process are not completely understood. Recent advances in high-throughput technologies along with concomitant advances in data analytics have enabled monitoring of cells at the single-cell level and increased the research focus on upstream cellular factors involved in the efficacy of immunotherapy, particularly the role of T cells. As our appreciation of different T cell subsets and their plasticity increases, the initial simplistic view that restoring Th1/Th2 balance by decreasing Th2 or increasing Th1 responses can ameliorate food allergy is being enhanced by a more complex model involving other T cell subsets, particularly Tregs. In this Review, we focus on the current understanding of T cell functions in food allergy, tolerance, and immunotherapy.

Cross-linking of shrimp tropomyosin catalyzed by transglutaminase and tyrosinase produces hypoallergens for potential immunotherapy

Transglutaminase or tyrosinase treatment reduces tropomyosin allergenicity and produces potential hypoallergens for immunotherapy.

Bifidobacterium lactis Ameliorates the Risk of Food Allergy in Chinese Children by Affecting Relative Percentage of Treg and Th17 Cells

We aimed to explore the therapeutic effect of Bifidobacterium lactis on food allergy by investigating the percentage of Treg and Th17 cells in Chinese children and related molecular mechanisms. A total of 256 children with food allergy were evenly assigned into two groups: BG, the children received 10 ml B. lactis (1 × 10⁶/ml) daily, and CG, the children received the solution without B. lactis daily for three months. Allergic symptoms, serum IgE, and food antigen-specific IgE were measured. A mouse allergy model was established by using shrimp tropomyosin and treated with B. lactis. Relative mRNA levels of Treg- and Th17-associated cytokines were measured by using quantitative PCR. The percentage of Treg and Th17 cells in spleen were measured by using flow cytometry. After 3-month therapy, the allergic symptoms of the BG were remarkably reduced when compared with the CG (P < 0.05). Serum levels of IgE and food antigen-specific IgE were decreased too (P < 0.05). Similar results were also found in a mouse allergy model. After B. lactis treatment, the relative mRNA level of FoxP3 was significantly enhanced in the B. lactis therapy group when compared to positive controls. In addition, relative mRNA levels of FoxP3 and TGF-β associated with Treg cells were increased, whereas relative mRNA levels of IL-17A and IL-23 associated with Th17 were reduced. B. lactis treatment significantly increased the ratio of Treg and Th17 cells in a mouse allergy model (P < 0.05). B. lactis effectively alleviates allergic symptoms by increasing the ratio of Treg and Th17 cells.

Immunomodulatory effects of probiotics: Can they be used to treat allergies and autoimmune diseases?

As a person ages, physiological, immunological and gut microbiome changes collectively result in an array of chronic conditions. According to the 'hygiene hypothesis' the increasing prevalence of immune-mediated disorders may be related to intestinal dysbiosis, leading to immune dysfunction and associated conditions such as eczema, asthma, allergies and autoimmune diseases. Beneficial probiotic bacteria can be utilized by increasing their abundance within the gastrointestinal lumen, which in turn will modulate immune cells, such as, T helper (Th)-1, Th2, Th17, regulatory T (Treg) cells and B cells, which have direct relevance to human health and the pathogenesis of immune disorders. Here, we describe the cross-talk between probiotics and the gastrointestinal immune system, and their effects in relation to inflammatory bowel disease, multiple sclerosis, allergies and atopic dermatitis.

Probiotic Species in the Modulation of Gut Microbiota: An Overview

Probiotics are microbial strains that are beneficial to health, and their potential has recently led to a significant increase in research interest in their use to modulate the gut microbiota. The animal gut is a complex ecosystem of host cells, microbiota, and available nutrients, and the microbiota prevents several degenerative diseases in humans and animals via immunomodulation. The gut microbiota and its influence on human nutrition, metabolism, physiology, and immunity are addressed, and several probiotic species and strains are discussed to improve the understanding of modulation of gut microbiota. This paper provides a broad review of several Lactobacillus spp., Bifidobacterium spp., and other coliform bacteria as the most promising probiotic species and their role in the prevention of degenerative diseases, such as obesity, diabetes, cancer, cardiovascular diseases, malignancy, liver disease, and inflammatory bowel disease. This review also discusses a recent study of Saccharomyces spp. in which inflammation was prevented by promotion of proinflammatory immune function via the production of short-chain fatty acids. A summary of gut microbiota alteration with future perspectives is also provided.