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Abstract Background Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of stacked β-amyloid peptides in the brain and associated with the generation of oxidative stress. So far, there is no cure for AD or a way to stop its progression. Although the neuroprotective effects of Ganoderma lucidum aqueous extract and G. lucidum-derived triterpenoids and polysaccharides have been reported, the influence of G. lucidum-fermented crops on AD still lacks clarity. Methods This study aimed to investigate the protective effect of G. lucidum-fermented crop extracts against hydrogen peroxide- or β-amyloid peptide (Aβ25-35)-induced damage in human neuroblastoma SH-SY5Y cells. Results Various extracts of G. lucidum-fermented crops, including extract A: 10% ethanol extraction using microwave, extract B: 70˚C water extraction, and extract C: 100˚C water extraction followed by ethanol precipitation, were prepared and analyzed. Extract B had the highest triterpenoid content. Extract C had the highest total glucan content, while extract A had the highest gamma-aminobutyric acid (GABA) content. The median inhibitory concentration (IC50, mg/g) for DPPH and ABTS scavenging activity of the fermented crop extracts was significantly lower than that of the unfermented extract. Pretreatment with these extracts significantly increased the cell viability of SH-SY5Y cells damaged by H2O2 or Aβ25-35, possibly by reducing cellular reactive oxygen species (ROS) and malondialdehyde (MDA) levels and increasing superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities. Moreover, extract B markedly alleviated the activity of acetylcholinesterase (AChE), which is crucial in the pathogenesis of AD. Conclusion These results clearly confirmed the effects of G. lucidum-fermented crop extracts on preventing against H2O2- or Aβ25-35-induced neuronal cell death and inhibiting AChE activity, revealing their potential in management of AD.

Grain processing produces many by-products, including wheat bran, wheat germ and rice bran, which are rich in carbohydrates, proteins and trace elements. In this study, these grain-derived by-products were used as raw materials to conduct solid-state fermentation using mixed strains of Aspergillus kawachii and Rhizopus oryzae, and the potential immunomodulatory and anti-allergic properties of fermented product were evaluated. Solid-state fermentation of a grain by-product mixture, consisting of rice bran, wheat bran, and wheat germ in a 2:1:1 weight ratio, using both A. kawachii L1 and R. oryzae L1 at 26 °C for 5 days, significantly increased the total phenolic, flavonoid, and amino acid contents. The anti-allergic activity of aqueous extract of the fermented product was evaluated in murine models of food allergy and delayed-type hypersensitivity. Oral administration of the fermented product extract (100–200 mg/kg) notably alleviated allergic symptoms such as diarrhea and histopathological changes in the intestines. Moreover, the extract effectively reduced allergen-specific serum antibodies, suppressed splenic cytokine secretion, and mitigated tissue edema and inflammation induced by allergens. Importantly, the extract induced the production of IL-10 and TGF-β, which are well-known cytokines primarily secreted by regulatory T cells. These results underscore the promising immunomodulatory effects of A. kawachii and R. oryzae fermented grain product, suggesting their potential as functional foods or additives for managing allergic disorders, with implications for future therapeutic and dietary applications.

Background: Cordyceps militaris is recognized as a tonic in traditional Chinese medicine, and there have been documented findings on the anti-allergic properties of its extract derived from the fruiting body. Due to the limited availability of wild C. militaris, a specialized grain substrate has been devised for the solid-state fermentation of its fruiting bodies. However, the fermented grain substrate is considered waste and usually used as feeds for animals. To achieve the sustainable development goals, C. militaris-fermented grain substrate (CFGS) was collected to prepare CFGS extracts. Further, the anti-allergic properties of these extracts were assessed with the aim of exploring novel applications. Methods: The water extract and ethanol extract of CFGS were prepared, and their potential in alleviating allergic enteritis was assessed in mice with food allergy. Assessment of immunomodulatory effects included the measurement of serum antibodies and splenic cytokines. Additionally, influence of extracts on gut microbiota composition was examined through sequencing analysis of 16S rRNA gene from freshly collected feces of the mice. Results: Daily administration of the water and ethanol extracts, at doses of 50 or 250 mg/kg body weight, demonstrated a notable alleviation of allergic diarrhea and enteritis. This was accompanied by a decrease in mast cell infiltration in the duodenum and a reduction in allergen-specific IgE production in the serum. Both extracts led to a significant decrease in IL-4 secretion. Conversely, there was an increase in IFN-γ, IL-10, and TGF-β secretion from splenocytes. Remarkably, allergic mice exhibited a distinct fecal microbiota profile compared to that of normal mice. Intriguingly, the administration of these extracts had varying effects on the fecal microbiota. Conclusion: Taken together, these findings collectively indicate the potential of CFGS extracts as promising candidates for functional foods. These extracts show promise in managing allergic enteritis and modulating gut microbiota.

The medicinal benefits of green seaweed Ulva have been documented in traditional Chinese medicine literatures. Sulfated polysaccharides found in Ulva are recognized as the primary bioactive compounds, known for their immunomodulatory and anti-inflammatory properties. Despite this knowledge, the available information regarding anti-allergic activities of Ulva remains limited. The objective of this study was to prepare and characterize Ulva-derived polysaccharides (UP), oligosaccharides (UO), and residues (UR), followed by assessing their potential in improving allergic enteritis and gut microbiota in a murine model of ovalbumin (OVA)-induced food allergy. The immunomodulatory activities of UP, UO, and UR were evaluated by measuring the expression of serum antibodies, splenic cytokines and duodenal transcript factors of T cell subsets. The impact of UP, UO, and UR on enteric microbiota was explored by 16S rRNA gene sequencing analysis of fresh fecal samples from treated mice. Oral treatment of UP, UO, and UR noticeably attenuated allergic diarrhea and enteritis. Additionally, Ulva samples treatment decreased serum levels of IgG1 and OVA-specific IgE while increased the level of OVA-specific IgG. Enhanced production of IFN-γ and reduced production of IL-4 and IL-10 by splenocytes were observed in the treated mice. In parallel, Ulva samples treatment led to a decreased number of GATA3+ cells and an increased number of T-bet+ cells in the duodenum. However, the population of Foxp3+ cells was not significantly altered. Moreover, treatment of Ulva samples improved enteric dysbiosis evidenced by an increased abundance of Lactobacillus murinus, L. johnsonii, and L. reuteri, and a decreased abundance of Kineothrix alysoides, Lacrimispora saccharolytica, L. aerotolerans, and Erysipelotrichaceae in feces. In conclusion, UP, UO, and UR, which could modulate the Th1/Th2 immune balance, alleviate allergic enteritis and improve enteric dysbiosis in varying degrees, are potential to be developed into therapeutic agents for food allergy.

ABSTRACTRecently, there have been reports on the immunomodulatory properties of polysaccharides (PP), oligosaccharides (PO), and mixtures of PO/PP derived from Porphyra. To explore their potential in alleviating allergic responses and enteric dysbiosis, this study delved deeper into their effects using a murine model of food allergy. Daily administration of Porphyra samples mitigated allergic diarrhea, enteritis, and allergen-specific IgE production. Moreover, Porphyra samples exerted a significant reduction in the secretion of IL-2, IL-4, IFN-γ, and IL-17A, along with an elevation in the IL-10/IL-4 ratio in splenocytes upon allergen stimulation. Similarly, expression of IL-4 and IFN-γ in the duodenum was suppressed. Notably, allergic mice displayed a distinct fecal microflora profile compared to that of normal mice. Interestingly, PP and PO treatments exhibited different effects on improving enteric dysbiosis. These findings collectively suggest the potential of PP and PO as functional food candidates for the management of allergic enteritis and dysbiosis.

The prevalence of food allergy, a common immune disorder associated with enteric dysbiosis, has been increasing in recent decades. Although immune-enhancing activity of Sargassum-derived polysaccharides has been reported, the influence of Sargassum-derived polysaccharides extract (SP) and even oligosaccharides extract (SO) on alleviating allergic responses remains unclear. Herein, SP and SO were prepared, and the residues (SR) was also harvested. The immunomodulatory and anti-allergic activities of these Sargassum samples were investigated in a murine model of food allergy. Daily treatment of SO, SP and SR by gavage exerted distinctive effects on modulating serum antibody production, regulating systemic and intestinal T cell responses, suppressing pro-inflammatory cytokine production, and attenuating allergic enteritis. In parallel, the improvement of enteric dysbiosis was observed with Bacteroides acidifaciens and Akkermansia muciniphila as the predominant microbes in response to Sargassum samples. Collectively, SO, SP and SR are novel candidates for developing functional foods against allergic enteritis and dysbiosis.

Background: Candida albicans is the most prevalent fungal pathogen, affecting over 75% of women who have experienced candidal vaginitis. Given the identification of drug-resistant C. albicans strains, there is an urgent need to develop therapeutic methods for treating vaginal Candida infection. Polysaccharide is the major bioactive component of Cordyceps militaris, known to modulate immune responses and alleviate inflammation. Sesame oil is known with anti-microbial and anti-inflammatory activities. Methods: C. militaris polysaccharide was prepared and formulated with sesame oil to prepare emulsion and nanoemulsion, which are ideal mucosal delivery systems for both hydrophobic and hydrophilic compounds concurrently. The physical property and storage stability of these formulations were illustrated, and their effects on ameliorating vaginitis were investigated in a murine model of vaginal Candida infection. Results: C. militaris polysaccharide-containing nanoemulsion showed smaller particle size, lower polydispersity index, higher zeta-potential and better stability than emulsion. Intravaginal administration of C. militaris polysaccharide-containing nanoemulsion significantly attenuated C. militaris colonization and vaginitis. Notably, these formulations exerted distinct effects on modulating cell infiltration and splenic cytokine production. Moreover, different profile of vaginal microflora was observed among the treatment groups, revealing the potential action mechanisms of these formulations to mitigate vaginal Candida infection. Conclusion: C. militaris polysaccharide- and sesame oil-containing nanoemulsion is potential to be developed as intravaginal therapeutic strategy for C. albicans-induced vaginitis.

A growing number of people choose plant-based milk products to replace dairy for health reasons or veganism. Since fermentation is a promising method to improve the nutritional value of plant-based milk, this study aimed to establish the process of oat milk fermentation and to evaluate the effect of fermented oat milk (FOM) on modulating antigen-specific immune response in ovalbumin (OVA)-sensitized mice. The FOM was prepared by fermentation of oat milk with Streptococcus thermophilus, Lactobacillus bulgaricus and proteolytic L. rhamnosus. Addition of 1% glucose improved the process of fermentation. FOM was stable while stored at 4°C within seven days. Oral administration with FOM (0.4 and 2 g/kg body weight) did not alter the serum level of OVA-specific IgG and spleen index. However, FOM had comparable potency with commercial dairy yogurt to lower stimulation index, IL-2, IFN-γ and IL-4 production and to promote TGF-β and IL-10 secretion by OVA-stimulated splenocytes.

Although recent studies indicated the immune modulatory effects of Porphyra extract and derived polysaccharides, the impact of Porphyra-derived oligosaccharides on immune responses remains unclear. This study aimed to explore the influence of Porphyra-derived polysaccharides (PP), oligosaccharides (PO) and the PO/PP mixture on antigen-specific immune responses in ovalbumin (OVA)-sensitized mice. Daily treatment with PP, PO, or PO/PP mixture did not influence the body weight, spleen weight index, serum levels of total and OVA-specific IgG. However, the levels of IgG1, IgG2a, total and OVA-specific IgE were down-regulated. Furthermore, productions of IL-2, IFN-γ, IL-4, and IL17 from splenocytes were diminished in mice treated with PP, PO, and PO/PP mixture. In contrast, the secretion of IL-10 was slightly increased and the ratio of IL-10/IL-4 was markedly raised. These results demonstrated the modulatory effects of PP, PO, and PO/PP mixture on antigen-specific immune responses, revealing their potential to be developed as functional foods for immunomodulation.

We aim to investigate the hypoglycaemic and antioxidant effects of submerged Ganoderma lucidum cultures and elucidate the potential mechanisms behind these effects using a type 2 diabetic rat model. Diabetic rats were daily fed with a high-fat diet supplemented with 1% or 3% freeze-dried whole submerged cultures of G. lucidum or mycelia for 5 weeks. We observed significantly decreased fasting plasma glucose levels, homoeostasis model assessment equation-insulin resistance, and plasma glucose in oral glucose tolerance test. Furthermore, we observed increased levels of glycogen, hepatic hexokinase, glucose-6-phosphate dehydrogenase, and intestinal disaccharidase activities. G. lucidum supplement downregulated the plasma levels of aspartate aminotransferase, alanine aminotransferase, creatinine, and urea nitrogen as well as liver and kidney levels of thiobarbituric acid reactive substances. Based on the hypoglycaemic and antioxidant effects of G. lucidum submerged cultures, we recommend the potential application of these products as functional foods or additives for controlling type 2 diabetes. Abbreviations ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; BUN: Blood urea nitrogen; BW: Body weight; CREA: Creatinine; FPG: Fasting plasma glucose; G6Pase: Glucose-6-phosphatase; G6PD: Glucose-6-phosphate dehydrogenase; HOMA-IR: Homoeostasis model assessment of insulin resistance; OGTT: Oral glucose tolerance test; PTP: Protein tyrosine phosphatase; STZ: Streptozotocin; TBARS: Thiobarbituric acid reactive substances

Diabetic rats were daily fed with a high-cholesterol diet containing 1% or 3% freeze-dried whole submerged G. lucidum culture or its mycelia for 5 weeks. Body weight, adipose tissue weight and plasma triglyceride levels were reduced, while high-density lipoprotein-cholesterol levels were elevated in rats fed with G. lucidum powder supplement diets. Notably, G. lucidum supplements downregulated the activities of hepatic acetyl-CoA carboxylase, fatty acid synthase and lipoprotein lipase, but upregulated the activity of hormone-sensitive lipase in the perirenal adipose tissues. Moreover, G. lucidum supplements increased the faecal triglyceride excretion. Therefore, daily supplementation of submerged G. lucidum culture, especially mycelia, can ameliorate dyslipidemia and reduce visceral fat accumulation in diabetic rats fed with a high-fat diet, which is closely related to the modulation of lipid synthesis, metabolism, and excretion.

Although citrus peel is a waste material, it contains a variety of bioactive components. As our preliminary findings showed that citrus peels fermented with Saccharomyces cerevisiae T1 contained increased levels of anti-obesity flavonoids, the objective of this study was to prepare fermented citrus peel and to investigate its effect on ameliorating obesity in Sprague Dawley (SD) rats fed with a high-fat diet (HFD). After fermentation, the amounts of limonene, nobiletin and 3-methoxynobiletin in citrus peel were markedly increased. SD rats were fed with an HFD for 10 weeks, followed by fermented citrus peel-containing HFD (0.3% or 0.9% w/w) for 6 weeks. Compared with those fed with an HFD alone, lower levels of body weight, visceral fat, body fat percentage, blood triglyceride, total cholesterol, low-density lipoprotein, malondialdehyde and hepatic adipose accumulation were observed in rats fed with fermented citrus peel. In parallel, hepatic levels of acetyl-CoA carboxylase and fatty acid synthase were diminished, and the level of hormone sensitivity lipase in visceral fat was elevated. These results reveal fermented citrus peel is a promising natural product with beneficial effects of alleviating HFD-induced obesity.

This study describes the assessment of mucosal adjuvant activity of a squalene-based nanoemulsion (SQ@NE) following intravaginal delivery in mice. After immunization, a high level of recruitment of CD11b/c+ granulocytes and F4/80+ macrophages was observed in the vaginal mucosal tissues of the mice immunized with a model protein ovalbumin (OVA) formulated with SQ@NE, and then downstream regulated the expression of MHC II and costimulatory molecules CD40 and CD86 on CD11c+ cells harvested from the associated draining lymph node. With respect to cytotoxic T lymphocyte immunity, the mice immunized with SQ@NE-formulated OVA elicited a high population of OVA-specific CD8+ cells in the spleen and increased the secretion of IFN-γ, IL-2 and IL-17 from OVA-restimulated splenocytes compared with those immunized with OVA alone. By studying in vivo fluorescence imaging and B-cell immunoassays, we discovered how SQ@NE prolongs the retention of antigen depots at the mucosal membrane of the immune inductive site and allows them to properly drive the production of antibodies. The data demonstrated that SQ@NE prolonged fluorescence-labeled OVA retention at the genital tract and augmented the production of OVA-specific IgG in sera and IgA in vaginal washes. These results indicate that SQ@NE is a promising vaginal adjuvant for the induction of both mucosal and systemic immune responses, a feature that provides implications for the development of a mucosal vaccine against genital infections and sexually transmitted diseases.

In 2020, approximately 9.3 billion tons of crustaceans were consumed, and 45–48% of shrimp shell (SS) by-products were discarded as waste. In this study, the SS of Litopenaeus vannamei was fermented by Lactobacillus plantarum LV33204, Stenotrophomonas maltophilia LV2122 (strong proteolytic activity), and Aeromonas dhakensis LV1111 (chitin-degrading activity), and the optimal fermentation conditions of liquid-fermented SS was established. Contents of total peptide, astaxanthin, and total phenolic content of the fermented SS were significantly higher than that of unfermented SS. In the presence of fermented SS, glucose uptake and insulin resistance of TNF-α-stimulated FL83B hepatocytes were markedly improved. Furthermore, daily oral supplement of fermented SS to streptozotocin (STZ)/nicotinamide (NA)-induced diabetic rats for 7 weeks significantly reduced plasma glucose and insulin resistance. Meanwhile, ingestion of fermented SS might enhance hepatic catabolism of glucose by increasing hexokinase and glucose-6-phosphate dehydrogenase activity and decreasing glucose-6-phosphatase activity. In addition, the fermented SS downregulated plasma total cholesterol (TG), triglycerides (TCs), low-density lipoprotein cholesterol (LDL-C), liver TG, and TC and lipid peroxidation levels in diabetic rats. In conclusion, a biorefinery process for waste SS was established through mixed strain fermentation. The in vitro and in vivo data reveal that the fermented SS is a promising functional food for the management of diabetic hyperglycemia and hyperlipidemia.

Hyperuricemia is a disease caused by a high level of uric acid in the blood. It is an important factor for gout and may be linked to renal and hepatic failure. The objective of this study was to investigate the hypouricemic effects of submerged culture of Ganoderma lucidum. The lyophilized powder of mycelium (GM) and extracellular polysaccharides (GP) of the G. lucidum submerged culture were prepared. The contents of hypouricemic components, including phenolics and flavonoids, in GM (34.33 ± 0.41 mg/g and 0.32 ± 0.01 mg/g) were higher than that in GP (20.52 ± 1.49 mg/g and not detected). The hypouricemic effect of GM and GP was evaluated in potassium oxonate (PO)-injected rats. The average food intake (23.3 ± 1.2 g/day) and body weight (355.7 ± 28.0 g) were decreased, and the serum level of uric acid (5.56 ± 0.41 mg/dL) was increased in PO-injected rats. However, allopurinol (10 mg/kg b.w.) or GM treatment (200 or 400 mg/kg b.w) improved food intake (26.3 ± 2.7 g/day) and reduced the level of uric acid (4.45 ± 0.46 mg/dL). In parallel, the activity of hepatic xanthine oxidase (XOD) was downregulated from 841.29 ± 299.58 μU/mg protein to 540.80 ± 199.20 μU/mg protein. Moreover, GM and GP (200 or 400 mg/kg b.w) alleviated the level of blood urea nitrogen (BUN) from 30.49 ± 4.71 to 21.16 ± 4.25 mg/dL. GP treatment also diminished the level of alanine transaminase (ALT) from 52.63 ± 18.82 to 27.35 ±6.82 U/L. These results clearly demonstrated the hypouricemic effect of submerged G. lucidum culture and their potential against hyperuricemia-associated renal and hepatic damage. GM was more potent to alleviate hyperuricemia, and GP was more potent to improve renal and hepatic function.

The hypoglycemic and antioxidant activities of Lactobacillus plantarum FPS 2520 and/or Bacillus subtilis N1 fermented soybean meal (SBM) in rats fed a high-fat diet (HFD) were investigated by assessing plasma glucose levels, insulin resistance, and oxidative stress-induced organ damage. Supplementation with FPS 2520- and/or N1-fermented SBM (500 and 1000 mg/kg of body weight per day) to HFD-induced obese rats for 6 weeks significantly down-regulated the concentration of plasma glucose during the oral glucose tolerance test (OGTT), as well as the concentration of fasting plasma glucose, insulin, and the value of the homeostasis model assessment of insulin resistance (HOMA-IR). In addition, plasma and hepatic levels of malondialdehyde (MDA) were alleviated in rats fed fermented SBM, especially SBM fermented by mixed strains. Moreover, fermented SBM treatment reduced HFD-exacerbated increases in plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and uric acid levels. Based on these results, we clearly demonstrate the effect of fermented SBM on improving insulin resistance and oxidation-induced organ damage. Therefore, it is suggested that fermented SBM has the potential to be developed as functional foods for the management of obesity-induced hyperglycemia and organ damage.

Background Emulsion adjuvants are a potent tool for effective vaccination; however, the size matters on mucosal signatures and the mechanism of action following intranasal vaccination remains unclear. Here, we launch a mechanistic study to address how mucosal membrane interacts with nanoemulsion of a well-defined size at cellular level and to elucidate the impact of size on tumor-associated antigen therapy.Methods The squalene-based emulsified particles at the submicron/nanoscale could be elaborated by homogenization/extrusion. The mucosal signatures following intranasal delivery in mice were evaluated by combining whole-mouse genome microarray and immunohistochemical analysis. The immunological signatures were tested by assessing their ability to influence the transportation of a model antigen ovalbumin (OVA) across nasal mucosal membranes and drive cellular immunity in vivo. Finally, the cancer immunotherapeutic efficacy is monitored by assessing tumor-associated antigen models consisting of OVA protein and tumor cells expressing OVA epitope.Results Uniform structures with ~200 nm in size induce the emergence of membranous epithelial cells and natural killer cells in nasal mucosal tissues, facilitate the delivery of protein antigen across the nasal mucosal membrane and drive broad-spectrum antigen-specific T-cell immunity in nasal mucosal tissues as well as in the spleen. Further, intranasal vaccination of the nanoemulsion could assist the antigen to generate potent antigen-specific CD8+ cytotoxic T-lymphocyte response. When combined with immunotherapeutic models, such an effective antigen-specific cytotoxic activity allowed the tumor-bearing mice to reach up to 50% survival 40 days after tumor inoculation; moreover, the optimal formulation significantly attenuated lung metastasis.Conclusions In the absence of any immunostimulator, only 0.1% content of squalene-based nanoemulsion could rephrase the mucosal signatures following intranasal vaccination and induce broad-spectrum antigen-specific cellular immunity, thereby improving the efficacy of tumor-associated antigen therapy against in situ and metastatic tumors. These results provide critical mechanistic insights into the adjuvant activity of nanoemulsion and give directions for the design and optimization of mucosal delivery for vaccine and immunotherapy.

Although the hypoglycemic potential of brewer’s yeast extract has been reported, there is limited information pertaining to the hypoglycemic ingredients of Saccharomyces pastorianus extract and their mechanisms of action available. This study aimed to investigate the in vivo and in vitro hypoglycemic effect of S. pastorianus extract and to elucidate its molecular mechanisms. S. pastorianus extract was mainly composed of proteins followed by carbohydrates. In diabetic rats, oral administration of S. pastorianus extract significantly reduced the levels of plasma glucose and enhanced the activity of hepatic glucose-6-phosphatase dehydrogenase. Treatment with S. pastorianus extract increased the localization of type 4 glucose transporter (GLUT4), PTP, and insulin receptor at 3T3-L1 cell membranes and raised the levels of P38 MAPK, PI3K, and AKT in the cytosol. In agreement with these results, pretreatment of 3T3-L1 cells with inhibitors of PTP, PI3K, Akt/PKB, and p38 MAPK inhibited glucose uptake induced by application of S. pastorianus extract. Most importantly, a 54 kDa protein with hypoglycemic activity was identified and suggested as the major ingredient contributing to the hypoglycemic activity of S. pastorianus extract. In summary, these results clearly confirm the hypoglycemic activity of S. pastorianus extract and provide critical insights into the underlying molecular mechanisms.

The effect of Lactobacillus reuteri against food allergy was investigated in ovalbumin (OVA)-sensitized BALB/c mice. Oral administration with L. reuteri restored the deteriorated profile of enteric flora, and attenuated allergic diarrhoea, mast cell activation, and serum IgE production in allergic mice. The production of signature T helper (Th)1 and 2 cytokines, namely IFN-γ and IL-4, by splenocytes was suppressed by L. reuteri. Concordantly, the intestinal expression of IFN-γ, IL-4, T-bet and GATA3 was down-regulated. However, L. reuteri augmented the expression of IL-10, TGF-β and Foxp3, and the number of IL-10-secreting CD11c+CD103+ mesenteric lymph node (MLN) cells. Furthermore, direct exposure to heat-killed L. reuteri attenuated OVA-induced cell proliferation and IL-2 secretion by MLN cells. These results demonstrate that L. reuteri possesses anti-allergic activities via modulating enteric flora and promoting tolerogenic immune responses, and suggest L. reuteri as a functional probiotic against food allergy.

The effect of antigen-adjuvant associations on antigen uptake and antigen-specific humoral immunity is studied in detail. After formulation with a squalene-based double emulsion (referred to as PELC), the protein ovalbumin (OVA) was intramuscularly injected in mice, in either a separation (OVA-PELCSE), a surface attachment (OVA-PELCSA) or an encapsulation (OVA-PELCEN) manner. As an antigen delivery system, a significant increase of OVA-loaded cells migrating into draining lymph nodes (LNs) was detected in the PELC-formulated OVA groups, attachment and encapsulation as well. Additionally, OVA-PELCEN allowed the mice to induce a delayed but long-lasting OVA-specific antibodies production compared to OVA-PELCSA. In the extreme case where no antigen-adjuvant association at all (i.e., OVA-PELCSE), we found that even with the presence of PELC at the contralateral limb, an elevated level of OVA uptake was detected in ipsilateral draining CD11c+ LN cells, which subsequently augmented the production of OVA-specific IgG antibodies during early vaccination. The mouse study allows us to find out the optimal vaccine formulation and deepens our understandings on how antigen-adjuvant associations can govern the cellular uptake and transportation of protein antigen into the draining LNs and prolong antigen-specific humoral immunity, even if the antigen and the adjuvant are given separately.

Although the anti-allergic and prebiotic activities of diosgenin have been reported, the influence of diosgenin on intestinal immune and epithelial cells remains unclear. As the gut microbiota plays an important role in allergic disorders, this study aimed to investigate whether the anti-allergic diarrhea effect of diosgenin occurs via improving gut dysbiosis. In a murine food allergy model, the density of fecal bacterial growth on de Man, Rogossa and Sharpe (MRS) plates was diminished, and growth on reinforced clostridial medium (RCM) and lysogeny broth (LB) agar plates was elevated. However, the oral administration of diosgenin reduced the density of fecal bacteria and ameliorated diarrhea severity. Concordantly, reshaped diversity and an abundance of fecal microbes were observed in some of the diosgenin-treated mice, which showed a milder severity of diarrhea. The relevant fecal strains from the diosgenin-treated mice were defined and cultured with Caco-2 cells and allergen-primed mesenteric lymph node (MLN) cells. These strains exhibited protective effects against the cytokine/chemokine network and allergen-induced T-cell responses to varying degrees. By contrast, diosgenin limitedly regulated cytokine production and even reduced cell viability. Taken together, these findings show that diosgenin per se could not directly modulate the functionality of intestinal epithelial cells and immune cells, and its anti-allergic effect is most likely exerted via improving gut dysbiosis.

The probiotic activity of Lactobacillus murinus against food allergy was investigated. Oral administration with L. murinus restored the deteriorated profile of enteric flora in mice with food allergy and attenuated allergic responses, including allergen-induced diarrhoea, mast cell activation, and serum IgE production. The production of IFN-γ and IL-4 by splenocytes was enhanced and suppressed, respectively, by L. murinus administration. Concordantly, a decreased expression of IL-4 and GATA3 and an increased expression of IFN-γ and T-bet were observed in the duodenum. Moreover, L. murinus enhanced IL-12 production and suppressed OX40 ligand expression by intestinal CD11c+ cells. Direct exposure to heat-killed L. murinus enhanced IFN-γ secretion by mesenteric lymph node cells. These findings demonstrate that L. murinus possesses anti-allergic activities via modulating enteric flora, intestinal CD11c+ cell functionality and the Th1/Th2 immunobalance, and suggest that L. murinus may be employed as a functional probiotic against food allergy.

Human infections with highly pathogenic avian influenza H5N1 viruses persist as a major global health concern. Vaccination remains the primary protective strategy against H5N1 and other novel avian influenza virus infections. We investigated the use of E. coli type IIb heat labile enterotoxin B subunit (LTIIb-B5) as a mucosal adjuvant for intranasal immunizations with recombinant HA proteins against H5N1 avian influenza viruses. Use of LTIIb-B5 adjuvant elicited more potent IgG, IgA, and neutralizing antibody titers in both sera and bronchoalveolar lavage fluids, thus increasing protection against lethal virus challenges. LTIIb-B5 mucosal adjuvanticity was found to trigger stronger Th17 cellular response in spleen lymphocytes and cervical lymph nodes. Studies of anti-IL-17A monoclonal antibody depletion and IL-17A knockout mice also suggest the contribution from Th17 cellular response to anti-H5N1 protective immunity. Our results indicate a link between improved protection against H5N1 live virus challenges and increased Th17 response due to the use of LTIIb-B5 mucosal adjuvant with HA subunit proteins.

Human infections with H7N9 avian influenza A virus can result in severe diseases with high mortality. Developing an effective vaccine is urgently needed to prevent its pandemic potential. Vaccine delivery routes via mucosal surfaces are known to elicit mucosal immune responses such as secretory IgA antibodies in mucosal fluids, thus providing first-line protection at infection sites. PEG-b-PLACL (PELC) is a squalene-based oil-in-water emulsion adjuvant system that can enhance antigen penetration and uptake in nasal mucosal layers with enhanced mucin interactions. In this study, intranasal immunizations with recombinant H7 (rH7) proteins with a PELC/CpG adjuvant, as compared to the use of poly (I:C) or bacterial flagellin adjuvant, elicited higher titers of H7-specific IgG, IgA, hemagglutination inhibition, and neutralizing antibodies in sera, and increased numbers of H7-specific IgG- and IgA-antibody secreting cells in the spleen. Both PELC/CpG and poly (I:C) adjuvants at a dose as low as 5 μg HA provided an 80% survival rate against live virus challenges, but a lower degree of PELC/CpG-induced Th17 responses was observed. Therefore, the mucosal delivery of rH7 proteins formulated in a PELC/CpG adjuvant can be used for H7N9 mucosal vaccine development.

Ulva, an edible green alga, contains sulfated polysaccharides and oligosaccharides that possess immunomodulatory and anti-inflammatory properties. The objective of this study was to investigate the anti-allergic effects of Ulva-derived samples of polysaccharides (UP), oligosaccharides (UO), and residues (UR) on delayed-type hypersensitivity (DTH) in mice. Oral treatment of mice with UP, UO, and UR (250 mg/kg body weight) daily noticeably improved the DTH reaction as evidenced by attenuation of footpad swelling and cell infiltration at the allergen-challenge site. Although the Ulva samples had limited impacts on the production of serum total IgG, decreased concentrations of allergen-specific IgG and IgG2a and an increased concentration of IgG1 were observed in the treated mice. Moreover, treatment with them suppressed allergen-induced IFN-γ and TNF-α secretion and elevated IL-4 secretion. However, none of the Ulva sample treatments could modulate the production of IL-10. Concordantly, the in situ data reveal that the Ulva sample treatments suppressed IFN-γ and TNF-α expression at the allergen-injection site. These findings collectively suggest the potential of UP, UO, and UR as functional food candidates for the management of delayed-type hypersensitivity. [ABSTRACT FROM AUTHOR]