Ingesting probiotic yogurt containing Lactiplantibacillus plantarum OLL2712 improves glycaemic control in adults with prediabetes in a randomized, double-blind, placebo-controlled trial.

AIM: The ingestion of Lactiplantibacillus plantarum OLL2712 (OLL2712) cells has been shown to improve glucose metabolism by suppressing chronic inflammation in murine models and clinical studies. This study aimed to clarify the effect of OLL2712 on glycaemic control in healthy adults with prediabetes. MATERIALS AND METHODS: The study was a randomized, double-blind, placebo-controlled, parallel-group design. Adult participants with prediabetes [n = 148, glycated haemoglobin (HbA1c) range: 5.6%-6.4%, age range: 20-64 years] were assigned randomly to placebo or OLL2712 groups (n = 74/group) and administered daily for 12 weeks either conventional yogurt or yogurt containing >5 × 109 heat-treated OLL2712 cells, respectively. In addition, the participants were followed for 8 weeks after the discontinuation of either yogurt. The primary outcome was the changes in HbA1c levels at weeks 12 and 16 by analysis of covariance. RESULTS: The levels of HbA1c and glycoalbumin decreased significantly in both groups at week 12 in comparison with those at week 0, but only in the OLL2712 group at week 16. HbA1c levels decreased significantly at weeks 12 and 16 in the OLL2712 group in comparison with the placebo group (p = .014 and p = .006, respectively). No significant inter- and intragroup differences in HbA1c levels were observed at week 20. CONCLUSIONS: The ingestion of OLL2712 prevents the deterioration of glycaemic control and maintains the HbA1c levels within the normal range in adults with prediabetes; yogurt probably exhibits similar effects, which may contribute to reducing the risk of developing type 2 diabetes.

Physical and chemical properties of nabak (Zizyphus spina-christi) seed kernel and sweet pepper (Capsicum annuum L.) seed oils.

BACKGROUND: Nabak seed kernels and sweet pepper seeds, which are separated from the fruits and discarded as waste after processing or consumption, contain high levels of oils (30.19% and 19.57%, respectively). The chemical and thermal characteristics of nabak seed kernel oil (NSO) and sweet pepper seed oil (PSO) were investigated in this study. RESULTS: The NSO and PSO contained high levels of unsaturated fatty acids (84.1% and 86.5%, respectively), and the major fatty acid was oleic acid (57.3%) in NSO, but it was linoleic acid (69.4%) in PSO. The triacylglycerol (TAG) profiles show that NSO contained ten TAG species, three of which represented 87.1%, namely C54:3, C52:2 and C54:4, and triolein was the dominant (OOO, 47.0%). Pepper seed oil contained nine TAG molecular species, four of which represented 93.6%, namely C54:6, C52:4, C54:4 and C52:5, and trilinolein was dominant (LLL, 44.0%). The differential scanning calorimetry (DSC) analysis of NSO revealed that three exothermal peaks were detected during cooling, two endothermal peaks were detected during melting, and the major peak occurred at a low temperature. For PSO, three exothermal peaks were detected during cooling, three peaks were detected (one of them was exothermal) during melting, and the major peaks were observed at low temperatures. Fourier transform infrared (FTIR) spectra indicated that NSO and PSO did not contain peroxides or trans fatty acids, but they did contain low concentrations of free fatty acids. CONCLUSION: This study offers a scientific basis for the use of NSO and PSO as new sources of edible oils for food applications. © 2021 Society of Chemical Industry.

Induction of Oral Tolerance by Pepsin-Digested Gliadin Retaining T Cell Reactivity in a Mouse Model of Wheat Allergy.

BACKGROUND: Wheat is known as the most widely consumed food all over the world. Although many types of wheat allergy have been recognized, their treatment still has a long way to go due to the complex pathogenesis. Oral immunotherapy (OIT) is under investigation for the treatment of wheat allergies. Previous studies have demonstrated that OIT using intact wheat allergens can induce tolerance, but is accompanied by a high risk of anaphylactic reactions. OBJECTIVES: Our objective was to prepare modified wheat allergens with hypoallergenic and tolerance-inducing properties to reduce adverse effects during immunotherapy. METHODS: Wheat gliadin was degraded by hydrolysis with pepsin and trypsin, and then the hydrolysate was deamidated with hydrochloric acid. The IgE-binding capacity and T cell reactivity of the degraded gliadins were evaluated in vitro. Pepsin-digested gliadin (peptic-GLI) was applied in a mouse model to investigate whether it would induce oral tolerance. RESULTS: Degradation with pepsin decreased IgE-binding capacity and maintained T cell reactivity. Oral administration of peptic-GLI to mice before sensitization and challenge with gliadin could significantly suppress the production of IgE, IgG1, and type 2 T helper cytokines. Moreover, the development of anaphylactic reactions and allergic responses of the small intestine induced by gliadin challenge were inhibited by oral administration of peptic-GLI. CONCLUSIONS: The findings of this study indicate that peptic-GLI with low allergenicity and potential for tolerance induction may become useful in wheat immunotherapy with less adverse effects.

Improved preparation of group-specific component (Gc) protein to derive macrophage activating factor.

Cancer immunotherapy has recently attracted attention as an approach for cancer treatment through the activation of the immune system. Group-specific component (Gc) protein is a precursor for macrophage activating factor (GcMAF), which has a promising immunomodulatory effect on the suppression of tumor growth and angiogenesis. In this study, we successfully purified Gc protein from human serum using anion-exchange chromatography combined with affinity chromatography using a 25-OH-D3-immobilized column. The purity of Gc protein reached 95.0% after anion-exchange chromatography. The known allelic variants of Gc protein are classified into three subtypes-Gc1F, Gc1S and Gc2. The fragment sequence of residues 412-424 determined according to their MS/MS spectra is available to evaluate the subtypes of Gc protein. The data showed that the Gc protein purified in this study consisted of the Gc1F and Gc2 subtypes. Our method improved the purity of Gc protein, which was not affected by the treatment to convert it into GcMAF using ß-galactosidase- or neuraminidase-immobilized resin, and will be useful for biological studies and/or advanced clinical uses of GcMAF, such as cancer immunotherapy.

Immunomodulation by food: impact on gut immunity and immune cell function.

Recent studies have revealed that various food components affect the immune response. These components act on various immune cells, and their effects are mediated through the intestinal immune system and, in some cases, the intestinal microbiota. In this review, we describe the immunomodulating effects of various food components, including probiotics, prebiotics, polysaccharides, vitamins, minerals, fatty acids, peptides, amino acids and polyphenols. Some of these components enhance immune responses, leading to host defense against infection, whereas others inhibit immune responses, thus suppressing allergy and inflammation.

Milk basic protein supplementation exerts an anti-inflammatory effect in a food-allergic enteropathy model mouse.

To examine novel functions of milk basic protein (MBP) in T-cell-related inflammatory diseases, such as autoimmune diseases and allergies, we evaluated the effects of MBP on the causative responses of ovalbumin (OVA)-specific T cells in a food-allergic enteropathy model, OVA23-3 mice, which express an OVA-specific T-cell receptor gene. The OVA-specific CD4+ T cells of the mesenteric lymph nodes (MLN) from OVA23-3 mice were cultured with CD11c+ dendritic cells of MLN from BALB/cA mice in the absence or presence of MBP following stimulation with OVA; then the levels of CD69 expression and the levels of cytokine production by CD4+ T cells were measured to evaluate activation. The effects of MBP supplementation of OVA 23-3 mice were assessed by feeding a diet containing OVA (OVA diet) with or without MBP for 28 d. Intestinal inflammation, together with activation and cytokine production of CD4+ T cells by MLN, as well as femoral bone mineral density, were measured. In in vitro culture, MBP inhibited excess activation and IL-4 production by CD4+ T cells. The supplementation of MBP to the OVA diet attenuated OVA-specific IgE production in OVA-diet-fed OVA23-3 mice and slightly resolved developing enteropathy caused by excess IL-4 production by CD4+ T cells. Feeding OVA diet to OVA23-3 mice exhibited bone loss accompanied with enteropathy, whereas MBP supplementation prevented bone loss and increased osteoprotegerin, an osteoclastogenesis inhibitory factor, in the mice. The inhibition of T-cell-activation in both MLN and bone marrow by MBP supplementation may help prevent increased IgE levels caused by excessive IL-4 production and bone loss accompanied by enteropathy. Our findings show that MBP may help attenuate both T-cell-related inflammation and bone loss.

Mesenteric lymph node CD11b- CD103+ PD-L1High dendritic cells highly induce regulatory T cells.

Dendritic cells (DCs) in mesenteric lymph nodes (MLNs) induce Foxp3+ regulatory T cells to regulate immune responses to beneficial or non-harmful agents in the intestine, such as commensal bacteria and foods. Several studies in MLN DCs have revealed that the CD103+ DC subset highly induces regulatory T cells, and another study has reported that MLN DCs from programmed death ligand 1 (PD-L1) -deficient mice could not induce regulatory T cells. Hence, the present study investigated the expression of these molecules on MLN CD11c+ cells. Four distinct subsets expressing CD103 and/or PD-L1 were identified, namely CD11b+ CD103+ PD-L1High , CD11b- CD103+ PD-L1High , CD11b- CD103+ PD-L1Low and CD11b+ CD103- PD-L1Int . Among them, the CD11b- CD103+ PD-L1High DC subset highly induced Foxp3+ T cells. This subset expressed Aldh1a2 and Itgb8 genes, which are involved in retinoic acid metabolism and transforming growth factor-ß (TGF-ß) activation, respectively. Exogenous TGF-ß supplementation equalized the level of Foxp3+ T-cell induction by the four subsets whereas retinoic acid did not, which suggests that high ability to activate TGF-ß is determinant for the high Foxp3+ T-cell induction by CD11b- CD103+ PD-L1High DC subset. Finally, this subset exhibited a migratory DC phenotype and could take up and present orally administered antigens. Collectively, the MLN CD11b- CD103+ PD-L1High DC subset probably takes up luminal antigens in the intestine, migrates to MLNs, and highly induces regulatory T cells through TGF-ß activation.

Oral administration of ovalbumin after sensitization attenuates symptoms in a mouse model of food allergic enteropathy.

Oral immunotherapy (OIT) is a promising treatment of food allergy. To administer an appropriate oral dose of an allergenic component as OIT to individuals sensitized with a food allergen may prevent inducing food allergic inflammation in them. So we attempted to establish a mouse model to evaluate efficacy for oral administration of food allergen after sensitization. In BALB/c mice sensitized by injecting ovalbumin (OVA) with alum twice, OVA was administered before inducing inflammation by feeding the mice with egg white (EW) diet. Severe inflammatory responses, such as enteropathy, weight loss, IL-4 production, and increase of IgE antibody levels, were suppressed by administration with 4 mg of OVA 7 times before feeding EW diet. OVA administration alone induced a slight Th2 response, but no symptoms. The current study demonstrated that severe food allergic enteropathy could be prevented by pre-administration with appropriate dose of OVA to sensitized mice.

Memory B cells in the lung participate in protective humoral immune responses to pulmonary influenza virus reinfection.

After pulmonary virus infection, virus-binding B cells ectopically accumulate in the lung. However, their contribution to protective immunity against reinfecting viruses remains unknown. Here, we show the phenotypes and protective functions of virus-binding memory B cells that persist in the lung following pulmonary infection with influenza virus. A fraction of virus-binding B-cell population in the lung expressed surface markers for splenic mature memory B cells (CD73, CD80, and CD273) along with CD69 and CXCR3 that are up-regulated on lung effector/memory T cells. The lung B-cell population with memory phenotype persisted for more than 5 mo after infection, and on reinfection promptly differentiated into plasma cells that produced virus-neutralizing antibodies locally. This production of local IgG and IgA neutralizing antibody was correlated with reduced virus spread in adapted hosts. Our data demonstrates that infected lungs harbor a memory B-cell subset with distinctive phenotype and ability to provide protection against pulmonary virus reinfection.

Attenuation of migration properties of CD4+ T cells from aged mice correlates with decrease in chemokine receptor expression, response to retinoic acid, and RALDH expression compared to young mice.

Aging results in attenuation of abilities to mount appropriate immune responses. The influence of aging on CD4(+) T cell migration ability toward chemokines was investigated with young and aged mice. We found functional decline in migration ability toward CCL19 and also decreased CCR7 expression level in antigen-stimulated CD4(+) T cells from aged mice compared with those from young mice. Upon addition of retinoic acid (RA), CD4(+) T cells from aged mice showed decreased CCR9 expression level compared to young mice and the migration ability of CD4(+) T cells from aged mice toward CCL25 was attenuated compared to young mice. We also observed that the expression of RALDH2 mRNA was decreased in mesenteric lymph node dendritic cells from aged mice compared to those from young mice. These results demonstrate that attenuated migration abilities of CD4(+) T cells were observed in aged mice, which correlated with decreased chemokine receptor expression. Furthermore, the reduced production and response to RA by aging may be one of the causes of such attenuated migration abilities in the intestinal immune system.

Splenic stromal cells from aged mice produce higher levels of IL-6 compared to young mice.

Inflamm-aging indicates the chronic inflammatory state resulting from increased secretion of proinflammatory cytokines and mediators such as IL-6 in the elderly. Our principle objective was to identify cell types that were affected with aging concerning IL-6 secretion in the murine model. We compared IL-6 production in spleen cells from both young and aged mice and isolated several types of cells from spleen and investigated IL-6 mRNA expression and protein production. IL-6 protein productions in cultured stromal cells from aged mice spleen were significantly high compared to young mice upon LPS stimulation. IL-6 mRNA expression level of freshly isolated stromal cells from aged mice was high compared to young mice. Furthermore, stromal cells of aged mice highly expressed IL-6 mRNA after LPS injection in vivo. These results suggest that stromal cells play a role in producing IL-6 in aged mice and imply that they contribute to the chronic inflammatory condition in the elderly.

Lactococcus lactis subsp. cremoris YRC3780 modifies function of mesenteric lymph node dendritic cells to modulate the balance of T cell differentiation inducing regulatory T cells.

Introduction: The intestinal immune system plays a pivotal role in the induction of immune responses against food. In the case of T cell response, dendritic cells (DCs) are especially important. However, the regulation of immune responses to food by intestinal DCs has been poorly described. In this study, we analyzed the effect of Lactococcus lactis subsp. cremoris YRC3780, a lactic acid bacterial strain isolated from kefir, a traditional fermented milk product, on the immune responses induced by antigen presentation by intestinal DCs to T cells as well as the mechanism of action of these immunomodulatory effects. It has been shown that L. cremoris YRC3780 ameliorates the symptoms of pollinosis in both animal and human studies. Methods: CD11c+ cells from mesenteric lymph nodes (MLNs) of BALB/c mice were cultured as MLN DCs with L. cremoris YRC3780 and expression of genes inducing regulatory T cells (Tregs) was examined by qPCR. In addition, MLN DCs were cocultured with CD4+ T cells from DO11.10 transgenic mice expressing an ovalbumin (OVA)-specific TCR and the OVA antigen peptide and L. cremoris YRC3780. Induction of Tregs was examined by flow cytometry, gene expression was analyzed by DNA microarray and qPCR, and the production of cytokines was measured by ELISA. MLN DCs from TLR2-deficient mice and components of L. cremoris YRC3780 were used to examine the recognition of YRC3780 by MLN DCs. Results: L. cremoris YRC3780 enhanced the expression of genes involved in Treg induction in MLN DCs and induced Foxp3+CD4+T cells in an MLN DC and CD4+ T-cell co-culture system. The effect on MLN DCs was likely mediated by receptors other than TLR2. Together with microarray analyses of CD4+ T cell gene expression and cytokine ELISA, it was demonstrated that L. cremoris YRC3780 promoted the induction of Th1 and Tregs, and regulated the balance of Th1/Th2 and Treg/Th17 cells involving multiple genes via the antigen-presentation of MLN DCs. Discussion: Our findings provide insights into the modulation of intestinal immune responses mediated by DCs and the antiallergic effects of lactic acid bacteria.

Orally administered Lactiplantibacillus plantarum OLL2712 decreased intestinal permeability, especially in the ileum: Ingested lactic acid bacteria alleviated obesity-induced inflammation by collaborating with gut microbiota.

Introduction: Chronic inflammation caused by dietary obesity has been considered to induce lifestyle-related diseases and functional ingredients with anti-inflammatory effects are attracting attention. Although multiple studies on obesity had proved the anti-inflammatory effects of ingestion of lactic acid bacteria (LAB) and other functional ingredients on adipose tissue, the precise effects on the intestine, especially on the individual intestinal segments have not been made clear. In this study, we elucidated the mechanisms of Lactiplantibacillus plantarum (basonym: Lactobacillus plantarum) OLL2712 in suppressing obesity-induced inflammation using high fat diet (HFD)-fed mice obesity model. Methods: We orally administered heat-treated LAB to HFD-fed mice model, and investigated the inflammatory changes in adipose tissue and intestinal immune cells. We also analyzed gut microbiota, and evaluated the inflammation and permeability of the duodenum, jejunum, ileum and colon; four intestinal segments differing in gut bacteria composition and immune response. Results: After 3-week LAB administration, the gene expression levels of proinflammatory cytokines were downregulated in adipose tissue, colon, and Peyer's patches (PP)-derived F4/80+ cells. The LAB treatment alleviated obesity-related gut microbiota imbalance. L. plantarum OLL2712 treatment helps maintain intestinal barrier function, especially in the ileum, possibly by preventing ZO-1 and Occludin downregulation. Discussion: Our results suggest that the oral administration of the LAB strain regulated the gut microbiota, suppressed intestinal inflammation, and improved the gut barrier, which could inhibit the products of obesity-induced gut dysbiosis from translocating into the bloodstream and the adipose tissue, through which the LAB finally alleviated the inflammation caused by dietary obesity. Barrier improvement was observed, especially in the ileum, suggesting collaborative modulation of the intestinal immune responses by ingested LAB and microbiota.

Two distinct epitopes on the ovalbumin 323-339 peptide differentiating CD4⁺T cells into the Th2 or Th1 phenotype.

The epitopes for OVA323-339-specific CD4⁺T cells from OVA23-3 food allergy model and DO11.10 tolerant induction model mice were analyzed. We found that OVA23-3 CD4⁺T cells recognized the N-terminal region, showing strong proliferation and the Th2-phenotype, and that DO11.10 CD4⁺T cells recognized the C-terminal region, showing milder proliferation and a Th1-skewed response. These differences may regulate the responses of those mice to OVA-feeding, inflammation and tolerance.

Immunomodulation by Food: Novel Collaborations between Food Components and Microbiota.

Recent studies have revealed that various food components affect the immune response. It has been shown that such components could act on the intestinal immune system. On the other hand, intestinal microbiota and their metabolites affect intestinal immunity. Such findings suggest the possibility that food components could act on the intestinal immune system directly, indirectly through intestinal microbiota, or through collaborative immunomodulation by both.

Extracts of Gluconacetobacter hansenii GK-1 induce Foxp3+T cells in food-allergic mice by an IL-4-dependent or IL-4-independent mechanism.

The biological activities of acetic acid bacteria (AAB) as Gram-negative bacteria have attracted our interests, especially in their inhibitory effects on allergic responses. To clarify the underlying mechanism that improves allergic symptoms by ingestion of the AAB Gluconacetobacter hansenii, we examined whether different extracts of heat-killed G. hansenii GK-1 could reduce the interleukin (IL)-4 production of immune cells from food-allergic model of OVA23-3, transgenic mice with ovalbumin (OVA)-specific T-cell-receptor genes. A hot-water extract fraction (FII) of G. hansenii GK-1 significantly decreased the in vitro IL-4 production of spleen cells of OVA23-3 mice compared with those stimulated with OVA alone. The IL-4 inhibitory effect was also observed for FIV (purified lipopolysaccharide (LPS) fraction), but the activity was lower than for FII or LPS from Escherichia coli. Unlike LPS from Escherichia coli, FIV significantly inhibited the LPS-induced IL-6 production of the spleen cells. The addition of FII or FIV to a Foxp3+T cell-inducing culture showed that FII significantly promoted the rate of Foxp3+CD4+T cells of OVA-stimulated mesenteric lymph node cells from recombination-activating-gene (RAG)-2-deficient food-allergic inflammatory OVA23-3 (R23-3) mice with suppression of IL-4 production, while FIV induced Foxp3+T cells from RAG-2-deficient DO11.10 non-inflammatory mice. Structure analysis showed a lack of O-antigen in FIV, which seemed to lead to the weak biological activities of FIV observed. The present study suggests that extracts of G. hansenii GK-1 to inhibit IL-4 production of immune cells and/or promote regulatory T cell differentiation synergistically play important roles in improving allergic symptoms safely as well as normal condition.

Suppressive Effect of Lactococcus lactis subsp. cremoris YRC3780 on a Murine Model of Japanese Cedar Pollinosis.

Accumulating evidence suggests that Lactococcus lactis subsp. cremoris YRC3780 isolated from kefir has the potential to alleviate allergic responses. Herein, we investigated the effect of YRC3780 on a murine model of Japanese cedar pollinosis (JCP). BALB/c mice immunized with cedar pollen extract (CPE) exhibited an increase in serum immunoglobulin E and developed nasal inflammatory responses including sneezing, nasal hyperresponsiveness, and nasal eosinophil accumulation upon intranasal allergen challenge. These responses were suppressed by the oral administration of YRC3780, although the effects on CPE-induced sneezing response and eosinophil infiltration were not statistically significant. Total fecal microbiota diversity was not affected by allergen immunization and challenge or by YRC3780 administration. However, the abundances of Bifidobacteriales, Veillonellaceae, Lactococcus, and Lactococcus lactis were larger and that of Bacteroides was smaller in YRC3780-treated mice compared with those in CPE-challenged and YRC3780-untreated mice. Our findings suggest the usefulness of YRC3780 for alleviating JCP.

Crystallization and melting properties studied by DSC and FTIR spectroscopy of goldenberry (Physalis peruviana) oil.

The chemical and thermal characteristics of goldenberry pomace oil (GPO) and goldenberry seed oil (GSO) were investigated. GPO and GSO contained high levels of unsaturated fatty acids (90.1% and 85.1%, respectively), and the major fatty acid was linoleic (62.0% and 72.8%, respectively). Additionally, GPO contained eleven triacylglycerol (TAG) species, three of which represented 82.7%, namely C54:6, C54:4 and C52:4, and trilinolein was the dominant one (35.5%). GSO contained nine TAG species, two of which represented 80.3%, namely C54:6 and C52:4, and trilinolein was dominant (53.3%). The DSC analysis of GPO and GSO revealed that three exothermal peaks were detected during cooling. Three endothermal peaks (one of which is exothermal for GSO) were detected during melting, and the most significant peaks occurred at low temperatures. FTIR spectra indicated that GPO and GSO did not contain peroxides or trans fatty acids, but they did contain low concentrations of free fatty acids.