Lactobacillus plantarum isolated from kimchi suppress food allergy by modulating cytokine production and mast cells activation

Effects of hazelnut protein isolate-induced food allergy on the gut microenvironment in a BALB/c mouse model

Hazelnuts are reported as among the nuts that cause severe allergic reactions. However, few systematic studies exist on the changes in the gut microenvironment following hazelnut allergy. This study focused on the effects of hazelnut allergy on the duodenum, jejunum, ileum and colon microenvironment in vivo. We established a hazelnut protein isolate (HPI)-allergic mouse model, which was distinguished by the visible allergy symptoms, dropped temperatures and enhanced allergic inflammatory factor levels in serum, such as HPI-specific immunoglobulin E (sIgE), sIgG2a, interleukin-4, histamine, mouse mast cell protease-1, TNF-α, monocyte chemotactic protein-1 and lipopolysaccharide. For HPI sensitized mice, aggravated mast cell degranulation, severe morphologic damage and inflammatory cell infiltration were observed in the duodenum, jejunum, ileum, and colon, while goblet cell numbers were reduced in the duodenum, jejunum and ileum. Secretory IgA of the jejunum and tight junctions of the duodenum and jejunum were decreased significantly after HPI sensitization. There was no remarkable difference in the pH values of small intestinal contents, but the pH values of colonic contents were elevated, which was due to the decreased short-chain fatty acids (mainly acetate, propionate and butyrate) in the colon. The antioxidant capacity of both large and small intestinal contents declined after HPI sensitization, as evidenced by the increased malondialdehyde and decreased superoxide dismutase activity. HPI sensitization induced gut microbiota dysbiosis with decreased α diversity and altered β diversity in colonic contents. Spearman correlation analysis indicated that the increased characteristic genera, namely Bacteroides, Lactobacillus, Alloprevotella, Erysipelatoclostridium, Parabacteroides, and Helicobacter, played potentially synergistic roles in promoting allergy and gut microenvironment dysregulation.

Effects of Allergen-Specific and Non-Specific AGEs on the Allergenicity of Ovalbumin in a Mouse Model of Food Allergy

SCOPE

Epidemiologic studies suggest a link between the incidence of food allergy and the consumption of dietary advanced glycation end-products (AGEs). However, the pathogenic role of dietary AGEs in food allergy is largely unknown. This study aims to investigate the effect of allergen-specific and non-specific AGEs on the allergenic manifestation of ovalbumin (OVA), a typical food allergen in vivo.

METHODS AND RESULTS

OVA is glycated by methylglyoxal to prepare allergen-specific AGEs (i.e., OVA-AGE), and a standard AIN-93G diet is heated to obtain allergen-non-specific AGEs. A BALB/c mouse model orally sensitizes to OVA with different forms of AGEs is established and the outcomes are measured as clinical signs, specific antibodies, type-2/type-2 cytokines, immune cell subpopulations, intestinal barrier function, and gut microbiota (GM) composition. The OVA-AGE which has a lower immunoglobulin E (IgE)-binding level in vitro does not reduce the allergenicity of OVA but promotes a stronger T helper 2 cells (Th2)-response than native OVA in vivo. Both forms of AGEs up-regulate the expression of splenic RAGE and aggravate the destruction of gut barrier and GM dysbiosis, especially when exposes to non-relevant AGEs.

CONCLUSION

This study highlights the role of dietary AGEs in food allergy and helps to understand the biological consequences of immune-toxic compounds in modern diet.

Advances in the Study of Probiotics for Immunomodulation and Intervention in Food Allergy

Food allergies are a serious food safety and public health issue. Soybean, dairy, aquatic, poultry, and nut products are common allergens inducing allergic reactions and adverse symptoms such as atopic dermatitis, allergic eczema, allergic asthma, and allergic rhinitis. Probiotics are assumed as an essential ingredient in maintaining intestinal microorganisms' composition. They have unique physiological roles and therapeutic effects in maintaining the mucosal barrier, immune function, and gastrointestinal tract, inhibiting the invasion of pathogenic bacteria, and preventing diarrhea and food allergies. Multiple pieces of evidence reveal a significant disruptive effect of probiotics on food allergy pathology and progression mechanisms. Thus, this review describes the allergenic proteins as an entry point and briefly describes the application of probiotics in allergenic foods. Then, the role of probiotics in preventing and curing allergic diseases by regulating human immunity through intestinal flora and intestinal barrier, modulating host immune active cells, and improving host amino acid metabolism are described in detail. The anti-allergic role of probiotics in the function and metabolism of the gastrointestinal tract has been comprehensively explored to furnish insights for relieving food allergy symptoms and preventing food allergy.

Oral Intervention of Narirutin Ameliorates the Allergic Response of Ovalbumin Allergy

A new intervention was investigated for the induction of oral tolerance (OT) of OVA using narirutin by in vivo and in vitro experiments combined with network pharmacology and structural analysis of molecular docking. Narirutin (and its metabolism naringenin) has effects on OT by affecting B cell function, DCs, and T cell response by prediction. It was verified that narirutin could affect B cell function of secreting antibodies, thereby reducing the ability of DCs to absorb antigens by affecting GATA3, CCR7, STAT5, and MHCII expression and regulating T cell response by suppressing Th2 and improving Treg cells in vivo. Molecular docking showed that steric hindrance effects may be the reason for weaker binding energy with targets of narirutin. However, this does not mean that it has no bioactivity, for it can inhibit mast cell degranulation. This finding is interesting because it offers the possibility of using natural compounds to promote oral tolerance.

Lactobacillus plantarum strains attenuated DSS-induced colitis in mice by modulating the gut microbiota and immune response

Gut microbiota has become a new therapeutic target in the treatment of inflammatory Bowel Disease (IBD). Probiotics are known for their beneficial effects and have shown good efficacy in the clinical treatment of IBD and animal models of colitis. However, how these probiotics contribute to the amelioration of IBD is largely unknown. In the current study, the DSS-induced mouse colitis model was treated with oral administration of Lactobacillus plantarum strains to investigate their effects on colitis. The results indicated that the L. plantarum strains improved dysbiosis and enhanced the abundance of beneficial bacteria related to short-chain fatty acids (SCFAs) production. Moreover, L. plantarum strains decreased the level of pro-inflammatory cytokines, i.e., IL-17A, IL-17F, IL-6, IL-22, and TNF-α and increased the level of anti-inflammatory cytokines, i.e., TGF-β, IL-10. Our result suggests that L. plantarum strains possess probiotic effects and can ameliorate DSS colitis in mice by modulating the resident gut microbiota and immune response.

Probiotic strains alleviated OVA-induced food allergy in mice by regulating the gut microbiota and improving the level of indoleacrylic acid in fecal samples

Food allergy (FA) is a common immune disorder caused by food antigens. Probiotic strains showed alleviating effects on FA, such as the alleviation of FA pathological symptoms, serum OVA-sIgE levels, and the gut microbiota diversity and composition. The results showed that intragastric administration of Lactiplantibacillus plantarum CCFM1189, Limosilactobacillus reuteri CCFM1190, and Bifidobacterium longum CCFM1029 alleviated the weight loss and FA pathological symptoms of FA mice and decreased OVA-specific IgE and histamine (HIS) levels. CCFM1189 and CCFM1190 decreased IL-4, IL-5, and IL-13 levels, while CCFM1189 and CCFM 1029 decreased IL-17 levels. The gut microbiota analysis demonstrated that CCFM1189 increased the abundance of Akkermansia, while CCFM1190 improved immune regulation bacteria such as Faecalibaculum. CCFM1029 increased Bifidobacterium and the bacteria involved in short-chain fatty acid (SCFA) production, such as Dubosiella. L. plantarum CCFM1189 and L. reuteri CCFM1190 improved indoleacrylic acid levels in mouse fecal samples using untargeted metabolomics analysis. In conclusion, CCFM1189, CCFM1190, and CCFM1029 decreased Th2 immune responses and alleviated FA pathological symptoms by regulating the gut microbiota diversity and composition, and altering gut microbial metabolites, which could provide support in clinical tests and probiotic production in the future.

Natural immunomodulating substances used for alleviating food allergy

Food allergy is a serious health problem affecting more than 10% of the human population worldwide. Medical treatments for food allergy remain limited because immune therapy is risky and costly, and anti-allergic drugs have many harmful side effects and can cause drug dependence. In this paper, we review natural bioactive substances capable of alleviating food allergy. The sources of the anti-allergic substances reviewed include plants, animals, and microbes, and the types of substances include polysaccharides, oligosaccharides, polyphenols, phycocyanin, polyunsaturated fatty acids, flavonoids, terpenoids, quinones, alkaloids, phenylpropanoids, and probiotics. We describe five mechanisms involved in anti-allergic activities, including binding with epitopes located in allergens, affecting the gut microbiota, influencing intestinal epithelial cells, altering antigen presentation and T cell differentiation, and inhibiting the degranulation of effector cells. In the discussion, we present the limitations of existing researches as well as promising advances in the development of anti-allergic foods and/or immunomodulating food ingredients that can effectively prevent or alleviate food allergy. This review provides a reference for further research on anti-allergic materials and their hyposensitizing mechanisms.

Lactobacillus Casei Zhang Alleviates Shrimp Tropomyosin-Induced Food Allergy by Switching Antibody Isotypes through the NF-κB-Dependent Immune Tolerance

SCOPE

Shellfish allergy is an important cause of food allergy, and tropomyosin (TM) is the major allergen within shellfish. Probiotics are safe bacteria that benefit host health and nutrition and is proposed as a novel approach for treating immunological diseases, including food allergies.

METHODS AND RESULTS

The probiotic strain Lactobacillus casei Zhang (LcZ) isolated from koumiss is investigated for its capacity to modulate food allergy induced by TM in BALB/c mice. Oral administration of LcZ attenuated allergy symptoms and intestinal epithelial damage. Furthermore, flow cytometry, real-time quantitative PCR, and ELISA demonstrated that LcZ administration altered the development and function of dendritic cells (DCs), T cells, and B cells, finally resulting in the change of TM-specific antibody isotypes into a tolerogenic pattern. Moreover, an in vitro spleen cell culture model reveals that LcZ directly modulates regulatory tolerogenic DC and T cell development, dependent on the activation of the nuclear factor kappa B (NF-κB) signaling pathway.

CONCLUSION

This work indicates the ability of LcZ to alleviate TM-induced food allergy and demonstrates the involvement of the tolerogenic immune cells and NF-κB signaling pathway, indicating LcZ to be a potential immunomodulator and immunotherapy assistor.