The influence of small oligosaccharides on the immune system

Influence of dietary mannan-oligosaccharides supplementation on hematological characteristics, blood biochemical parameters, immune response and histological state of laying hens

This study aimed to determine the influence of dietary mannan-oligosaccharides (MOS) on the immune system, hematological traits, blood biochemical parameters, and histological state of laying hens. At 34 wk of age, The Mandarah chicken strain's 120 laying hens and 12 cocks were divided into 4 groups, each with 30 hens and 3 cocks. The first group performed as a control group, which nourished on a basal diet. The second, third, and fourth experimental groups received 0.1, 0.2, and 0.5 g/kg of MOS and a base diet, respectively. Birds obtained MOS at numerous doses significantly (P ˂ 0.05) raised serum levels of immunoglobulin Y (IgY), immunoglobulin M (IgM), and avian influenza (AI) antibodies compared to control birds. Furthermore, adding MOS at a level of 0.1 g/kg diet significantly improved the immune response of the control group. Additionally, compared to the control group, treated birds with MOS at various dosages did not significantly enhance hematological parameters such as red blood cells (RBCs), white blood cells (WBCs), hemoglobin, and hematocrit. Compared to control birds, birds fed MOS at all levels exhibited considerably lower serum cholesterol, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) values. Also, compared to other treated birds, MOS-treated birds displayed improved histological examination of the small intestine, isthmus, and testis compared to the control group, particularly in birds fed MOS at 0.1 and 0.2 g/kg diet. It could be concluded that using MOS at 0.1 or 2 g/kg diet can successfully improve the physiological performance and overall health of laying hens.

An Antioxidant Supplement Function Exploration: Rescue of Intestinal Structure Injury by Mannan Oligosaccharides after Aeromonas hydrophila Infection in Grass Carp (Ctenopharyngodon idella)

Mannan oligosaccharides (MOS) are a type of functional oligosaccharide which have received increased attention because of their beneficial effects on fish intestinal health. However, intestinal structural integrity is a necessary prerequisite for intestinal health. This study focused on exploring the protective effects of dietary MOS supplementation on the grass carp’s (Ctenopharyngodon idella) intestinal structural integrity (including tight junction (TJ) and adherent junction (AJ)) and its related signalling molecule mechanism. A total of 540 grass carp (215.85 ± 0.30 g) were fed six diets containing graded levels of dietary MOS supplementation (0, 200, 400, 600, 800 and 1000 mg/kg) for 60 days. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila for 14 days. We used ELISA, spectrophotometry, transmission electron microscope, immunohistochemistry, qRT-PCR and Western blotting to determine the effect of dietary MOS supplementation on intestinal structural integrity and antioxidant capacity. The results revealed that dietary MOS supplementation protected the microvillus of the intestine; reduced serum diamine oxidase and d-lactate levels (p < 0.05); enhanced intestinal total antioxidant capacity (p < 0.01); up-regulated most intestinal TJ and AJ mRNA levels; and decreased GTP-RhoA protein levels (p < 0.01). In addition, we also found several interesting results suggesting that MOS supplementation has no effects on ZO-2 and Claudin-15b. Overall, these findings suggested that dietary MOS supplementation could protect intestinal ultrastructure, reduce intestinal mucosal permeability and maintain intestinal structural integrity via inhibiting MLCK and RhoA/ROCK signalling pathways.

Enzymatic Conversion of Mannan-Rich Plant Waste Biomass into Prebiotic Mannooligosaccharides

A growing demand in novel food products for well-being and preventative medicine has attracted global attention on nutraceutical prebiotics. Various plant agro-processes produce large amounts of residual biomass considered "wastes", which can potentially be used to produce nutraceutical prebiotics, such as manno-oligosaccharides (MOS). MOS can be produced from the degradation of mannan. Mannan has a main backbone consisting of β-1,4-linked mannose residues (which may be interspersed by glucose residues) with galactose substituents. Endo-β-1,4-mannanases cleave the mannan backbone at cleavage sites determined by the substitution pattern and thus give rise to different MOS products. These MOS products serve as prebiotics to stimulate various types of intestinal bacteria and cause them to produce fermentation products in different parts of the gastrointestinal tract which benefit the host. This article reviews recent advances in understanding the exploitation of plant residual biomass via the enzymatic production and characterization of MOS, and the influence of MOS on beneficial gut microbiota and their biological effects (i.e., immune modulation and lipidemic effects) as observed on human and animal health.

Apple Pomace and Performance, Intestinal Morphology and Microbiota of Weaned Piglets-A Weaning Strategy for Gut Health?

Apple pomace (AP) is known to be rich in biomolecules beneficial for health and it may advantageously be used to overcome the critical step of piglets’ weaning. The study aimed to determine the effect of two levels of incorporation of AP on the performance, intestinal morphology, and microbiota of weaned piglets and investigate this feed ingredient as a weaning strategy. An experiment was performed with 42 piglets from weaning (28 days old) over a five-week period, including three iso-energetic and iso-nitrogenous diets (0%, 2%, and 4% dried AP diets) with seven pen-repetitions per diet (two pigs per pen). AP diets were beneficial for the average daily gain calculated on week 3 (p = 0.038) and some parameters of the intestinal architecture on the 35 post-weaning day. The 4% AP diet was beneficial for the feed conversion ratio (p = 0.002) and the energetic feed efficiency (p = 0.004) on the 35 post-weaning day. AP tended to influence the consistency of feces (softer to liquid, p = 0.096) and increased the counts of excreted pathogens (p = 0.072). Four percent AP influenced the richness of the microbiota and the bacteria profile as observed for the phylum Bacteroidetes or the class Clostridia. The 4% AP diet appeared as an interesting weaning strategy that should be evaluated in a large cohort.

The probiotic L. casei LC-XCAL™ improves metabolic health in a diet-induced obesity mouse model without altering the microbiome

Chronic low-grade inflammation associated with obesity may be a target for improvement of metabolic health. Some exopolysaccharide (EPS)-producing bacteria have been shown to have anti-inflammatory effects in gastrointestinal inflammatory conditions. However, evidence for the role of EPS-producing probiotics in the management of obesity and associated conditions is scarce and the role of the microbiota is unclear. In this study, two probiotic candidates were screened for their effects on metabolic health using the diet-induced obesity (DIO) mouse model. Mice fed a high-fat diet supplemented with the anti-inflammatory, EPS-producing strain L. caseiLC-XCAL™ showed significantly reduced hepatic triglycerides, hepatic total cholesterol, and fat pad weight compared to those fed a high-fat diet alone, likely as a result of reduced energy absorption from food. 16-S rRNA amplicon analysis of the fecal microbiota of these mice indicated that the altered metabolic phenotype as a result of the L. casei LC-XCAL strain administration was not associated with an overall change in the composition or inferred functional capacity of the fecal microbiota despite some abundance changes in individual taxa and functions. These findings provide evidence that specific microbial strategies can improve metabolic health independent of the microbiome and reinforce the importance of carefully selecting the most appropriate strain for specific indications by thorough screening programmes.

Radical Depolymerization of Alginate Extracted from Moroccan Brown Seaweed Bifurcaria bifurcata

The degradation of alginate extracted from Moroccan Bifurcaria bifurcata has not been fully established to date. In this work, we report the extraction and the characterization of alginate (ASBB) from the brown algae B. bifurcata, as well as the production of oligo-alginates (OGABs) by using a green chemistry process. The depolymerization of ASBB was carried out by controlled radical hydrolysis through our green chemistry process using a hydrogen peroxide (H2O2) catalyst. The molecular weight (Mw) and degree of polymerization (DP) distribution of oligo-alginates (OGABs) obtained were then characterized by HPLC size exclusion chromatography (SEC) and high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Structural characterization revealed that after 6 h of depolymerization of ASBB, we obtained OGABs with Mw ≤ 5.5 kDa and 2 ≤ DP ≤ 24. These results highlight the effectiveness of the controlled radical hydrolysis of alginate to produce good yields of alginate fractions with controlled Mw with a known polymerization degree (DP) and without altering properties of oligo-alginates. Bifurcaria bifurcata can be a potential source of alginate and oligo-alginates given its abundance on the northwest Atlantic coast. The production and characterization of oligo-alginates promote their exploitation in the cosmetic, pharmaceutic, and agriculture fields.

Immunomodulatory influences of sialylated lactuloses in mice

The aim of this study was to investigate the immune modulatory influences of sialylated lactuloses in mice. The effects of the four sialylated lactuloses by gavage methods on the weight gain rate, organ, serum and spleen immunoglobulin of mice were investigated. Neu5Ac-α2,3-lactulose group and Kdn-α2,3-lactulose group had significantly higher weight gain rate than control group. The weight gain rate, thymus index and spleen index of Kdn-α2,3-lactulose group were significantly higher than control group and lactulose group. Liver and small intestine of Neu5Ac-α2,3-lactulose group, Neu5Ac-α2,6-lactulose group and Kdn-α2,6-lactulose group showed different degree of damage. IgG levels of serum and spleen in Neu5Ac-α2,6-lactulose group and Kdn-α2,6-lactulose group were significantly higher than control group and lactulose group. The contents of IgG in serum and spleen of Kdn-α2,3-lactulose group were significantly lower than that of control group, while the contents of IgA and IgM in serum were significantly higher than those of control group. The IgA level increased by 12.23% and 58.77% comparing with lactulose group and control group, respectively. The IgM level in serum of Kdn-α2,3-lactulose group mice increased by 43.88% and 8.05% comparing with control group and lactulose group, respectively. The IgA level and IgM level in spleen of Kdn-α2,3-lactulose group mice increased by 49.05% and 47.25% comparing with control group. In short, Kdn-α2,3-lactulose is relatively safe and superior to use as a food supplement or potential drug candidate. Our results also indicate that some other sialylated oligosaccharides are potentially harmful to organisms, they may cause some side effects.

Enhancement of immune response and resistance against Vibrio parahaemolyticus in kuruma shrimp (Marsupenaeus japonicus) by dietary supplementation of β-1,4-mannobiose

Supplementation of prebiotic carbohydrates can act as a potent immunomodulator and have the efficacy to induce immune-related genes which are involved in host defense. Pure β-1,4-mannobiose (MNB) showed activation of prophenoloxidase system of shrimp hemocytes in vitro. The resistance of kuruma shrimp Marsupenaeus japonicus against Vibrio parahaemolyticus was examined after the shrimp were fed with 0 (control), 0.02, 0.2, and 2% MNB supplemented diets. The results showed significantly higher survival rates in MNB supplemented shrimp than those of the control one from 2 to 12 days post challenge. In another experiment, the hemocyte count, ROS production, phagocytic, phenoloxidase and bactericidal activities, and expression of immune-related genes were investigated in the control and MNB supplemented groups at day 1, 4, 6, 8 and 11 of the feeding. These immune parameters were significantly enhanced in MNB supplemented groups. Furthermore, the gene expression analysis showed that transcripts of lysozyme, crustin, penaeidin and TNF were significantly up-regulated in hemolymph, lymphoid organs and intestines of MNB treated shrimp. Overall, the results provided evidence that MNB supplementation could improve the immune response and increase shrimp resistance against V. parahaemolyticus infection.

Prebiotics: A Novel Approach to Treat Hepatocellular Carcinoma

Hepatocellular carcinoma is one of the fatal malignancies and is considered as the third leading cause of death. Mutations, genetic modifications, dietary aflatoxins, or impairments in the regulation of oncogenic pathways may bring about liver cancer. An effective barrier against hepatotoxins is offered by gut-liver axis as a change in gut permeability and expanded translocation of lipopolysaccharides triggers the activation of Toll-like receptors which stimulate the process of hepatocarcinogenesis. Prebiotics, nondigestible oligosaccharides, have a pivotal role to play when it comes to inducing an antitumor effect. A healthy gut flora balance is imperative to downregulation of inflammatory cytokines and reducing lipopolysaccharides induced endotoxemia, thus inducing the antitumor effect.

Effects of dietary concentrated mannan oligosaccharides supplementation on growth, gut mucosal immune system and liver lipid metabolism of European sea bass (Dicentrarchus labrax) juveniles

The study assesses the effects of dietary concentrated mannan oligosaccharides (cMOS) on fish performance, biochemical composition, tissue fatty acid profiles, liver and posterior gut morphology and gen expression of selected parameters involved on the intestinal immune response and liver lipid metabolism of European sea bass (Dicentrarchus labrax). For that purpose, specimens of 20 g were fed during 8 weeks at 0 and 1.6 g kg(-1) dietary cMOS of inclusion in a commercial sea bass diet. Dietary cMOS enhanced fish length, specific and relative growth without affecting tissue proximate composition. However, cMOS supplementation altered especially liver and muscle fatty acid profiles by reducing levels of those fatty acids that are preferential substrates for β-oxidation in spite of a preferential retention of long chain polyunsaturated fatty acids (LC-PUFA), such as 20:4n-6 or 22:5n-6, in relation to the down-regulation of delta 6/5 desaturase gene expression found in liver. Besides, dietary cMOS supplementation reduced posterior gut intestinal folds width and induced changes on the gene expression level of certain immune-related genes mainly by down regulating transforming growth factor β (TGFβ) and up-regulating immunoglobulin (Ig), major histocompatibility complex class II (MHCII), T cell receptor β (TCRβ) and Caspase 3 (Casp-3). Thus, dietary cMOS inclusion at 0.16% promoted European sea bass specific growth rate and length, stimulated selected cellular GALT-associated parameters and affected lipid metabolism in muscle and liver pointing to a higher LC-PUFA accumulation and promoted β-oxidation.

Effect of inulin and mannan-oligosaccharides compared with zinc-bacitracin on growing performance, nutrient digestibility and hematological profiles of growing rabbits

The study aimed to evaluate the effect of inulin and mannan-oligosaccharides (MOS) vs zinc-bacitracin (ZnB) on rabbit growth performance, nutrient digestibility, and blood profiles. In total, 108 rabbits 32 days of age were divided into four homogeneous groups fed the same basal diet and submitted to the following dietary treatments: control group, without supplementation; inulin group, supplemented with inulin (0.25 g/rabbit.day); MOS group, supplemented with MOS (0.083 g/rabbit.day); and ZnB group, supplemented with ZnB (0.083 g/rabbit.day). The supplements were administered 2 days per week from 32 to 81 days of age. At 32, 56 and 81 days, the rabbits were weighed and feed intake was measured. Mortality was recorded daily. Nutrient digestibility was measured at 65 days by an ingesta–excreta balance. Samples of blood were collected at 53, 67 and 81 days of age. The control group showed the highest (P < 0.01) mortality rate throughout the trial (17.0%), followed by ZnB (8.18%), inulin (3.7%) and then the MOS group, which had the lowest mortality (1.6%; P < 0.01). Addition of MOS led to a more favourable (P < 0.05) feed conversion ratio than addition of ZnB at 32–56 days of age and inulin for the entire trial period. The MOS group showed increased (P < 0.01) digestibility of dry matter, organic matter, ash and crude fibre relative to the control group. All supplements increased (P < 0.01) protein digestibility relative to the control. The level of alanine aminotransferase was reduced due to the use of feed supplements, and MOS supplementation gave the lowest (P < 0.01) value. Administration of prebiotics to growing rabbits as an alternative to ZnB can lead some advantages compared with both antibiotic and unsupplemented diets; MOS was more effective than inulin.

Sugar-coated: exopolysaccharide producing lactic acid bacteria for food and human health applications

The human enteric microbiome represents a veritable organ relied upon by the host for a range of metabolic and homeostatic functions.

The immunologically active oligosaccharides isolated from wheatgrass modulate monocytes via Toll-like receptor-2 signaling

Wheatgrass is one of the most widely used health foods, but its functional components and mechanisms remain unexplored. Herein, wheatgrass-derived oligosaccharides (WG-PS3) were isolated and found to induce CD69 and Th1 cytokine expression in human peripheral blood mononuclear cells. In particular, WG-PS3 directly activated the purified monocytes by inducing the expression of CD69, CD80, CD86, IL-12, and TNF-α but affected NK and T cells only in the presence of monocytes. After further purification and structural analysis, maltoheptaose was identified from WG-PS3 as an immunomodulator. Maltoheptaose activated monocytes via Toll-like receptor 2 (TLR-2) signaling, as discovered by pretreatment of blocking antibodies against Toll-like receptors (TLRs) and also determined by click chemistry. This study is the first to reveal the immunostimulatory component of wheatgrass with well defined molecular structures and mechanisms.

Intra- and extracellular antioxidant capacities of the new water-soluble form of curcumin (NDS27) on stimulated neutrophils and HL-60 cells

Phagocytic cells, especially neutrophils (PMNs) are specialized in the production of reactive oxygen species (ROS) to kill pathogenic agents, but an excessive ROS production is associated with tissue damages and inflammatory diseases. Phagocytes are thus prime therapeutic targets to control inflammatory events associated to ROS production. Nowadays, there is a growing interest for the use of polyphenols to modulate the inflammatory response. The aim of this work was to study the antioxidant effect of NDS27, a highly water-soluble form of the polyphenolic molecule curcumin, on in vitro stimulated equine PMNs and human promyelocytic leukemia cells (HL-60). NDS27 was either pre-incubated with cells and eliminated before their activation (intracellular effect) or let in the medium (extracellular effect). Our results indicate that NDS27 significantly and dose-dependently (10(-6) M-10(-4) M) inhibited the ROS production in both cell types without affecting their viability. NDS27 was able to cross and interact with cell membrane, especially for HL-60 cells, while we observed a better intracellular antioxidant effect with PMNs. The activity of myeloperoxidase (MPO) released by PMNs and HL-60 cells, was decreased by NDS27, but more efficiently for PMNs. These results suggested that the greater efficiency of NDS27 in PMNs is due to an inhibitory effect on cells which are more mature for ROS production, probably by targeting the enzymes implied in respiratory burst like MPO. The modulatory effect of NDS27 on the oxidant activity of cells involved in immune and inflammatory responses opens perspectives for a therapeutic control of pathologies with excessive inflammatory reactions.

Evaluation of immunostimulatory activities of synthetic mannose-containing structures mimicking the β-(1->2)-linked cell wall mannans of Candida albicans

Immunostimulatory properties of synthetic structures mimicking the β-(1→2)-linked mannans of Candida albicans were evaluated in vitro. Contrary to earlier observations, tumor necrosis factor (TNF) production was not detected after stimulation with mannotetraose in mouse macrophages. Divalent disaccharide 1,4-bis(α-D-mannopyranosyloxy)butane induced TNF and some molecules induced low levels of gamma interferon (IFN-γ) in human peripheral blood mononuclear cells (PBMC).

Structural characterization and immunological activities of the water-soluble oligosaccharides isolated from the Panax ginseng roots

Water-soluble ginseng oligosaccharides (designated as WGOS) with a degree of polymerization ranging from 2 to 10 were obtained from warm-water extract of Panax ginseng roots, and fractionated into five purified fractions (i.e., WGOS-0, WGOS-1, WGOS-2, WGOS-3, and WGOS-4) by gel-filtration chromatography. In order to ascertain the monosaccharide residues in the WGOS, a technique that combines acid hydrolysis and high-performance liquid chromatography was employed. It was found that only glucose residues were present in the WGOS. Fourier transform infrared spectroscopy and electrospray ionization tandem mass spectrometry provided the sequence, linkage, and configuration information. It is noteworthy that α-Glcp-(1 → 6)-α-Glcp, α-Glcp-(1 → 6)-α-Glcp-(1 → 4)-α-Glcp, α-Glcp-(1 → 6)-α-Glcp-(1 → 6)-α-Glcp-(1 → 4)-α-Glcp, and other six malto-oligosaccharides (i.e., maltopentaose, maltohexaose, maltoheptaose, maltooctaose, maltononaose, and maltodecaose) were detected in ginseng. Preliminary immunological tests in vitro indicated that WGOS were potent B and T-cell stimulators and WGOS-1 has the highest immunostimulating effect on lymphocyte proliferation among those purified fractions. It is hoped that the WGOS will be developed into functional food or medicine.

Mannan oligosaccharide increases serum concentrations of antibodies and inflammatory mediators in weanling pigs experimentally infected with porcine reproductive and respiratory syndrome virus

Mannan-containing products are capable of modulating immune responses in animals. However, different products may have diverse immunomodulation. The experiment was conducted to examine effects of mannan oligosaccharide (Actigen; ACT) on growth performance and serum concentrations of antibodies and inflammatory mediators in weanling pigs (Sus scrofa) experimentally infected with porcine reproductive and respiratory syndrome virus (PRRSV). A total of 32 PRRSV-negative pigs (3 wk old) were randomly assigned from within blocks to 1 of 4 treatments in a 2 by 2 factorial arrangement [2 types of diet: control (0%) and ACT addition (0.04%); and with and without PRRSV] in a randomized complete block design. Pigs were blocked by initial BW within sex. Ancestry was equalized across treatments. Pigs (8/treatment) were kept individually in each pen. After 2 wk of an 8-wk period of feeding the treatments, pigs received an intranasal inoculation of PRRSV or sham medium at 5 wk of age. Infection by PRRSV decreased ADG, ADFI, and G:F throughout the experiment (P < 0.01). Actigen did not affect ADG (P = 0.450), but decreased (P = 0.047) ADFI from 28 to 42 days postinoculation (DPI). During that time, ACT improved G:F in infected pigs but not in sham controls (interaction, P = 0.009). Dietary ACT did not affect viremia in infected pigs (P > 0.05), but increased PRRSV-specific antibody titer at 35 DPI (P = 0.042). Infection with PRRSV induced the febrile responses of pigs from 3 to 10 DPI (P < 0.001) with return to normal at 14 DPI. During the experimental period, the rectal temperature of pigs was found slightly elevated by ACT (P = 0.045). Infected pigs had greater serum concentrations of IL-1β, tumor necrosis factor (TNF)-α, IL-12, interferon (IFN)-γ, IL-10, and haptoglobin (Hp) than sham controls (P < 0.001). These results indicate that PRRSV stimulated secretion of cytokines involved in innate, T-helper 1, and T-regulatory immune responses. Actigen tended to decrease the serum TNF-α concentration regardless of PRRSV (P = 0.058). The ACT × PRRSV interaction was significant for IL-1β (P = 0.016), IL-12 (P = 0.026), and Hp (P = 0.047), suggesting that infected pigs fed ACT had greater serum concentrations of these mediators than those fed the control. The increases in IL-1β and IL-12 may favorably promote innate and T-cell immune functions in infected pigs fed ACT. Feeding ACT may be useful as ACT is related to increased PRRSV antibody titers and G:F in infected pigs at certain times during infection.

Effects of mannan oligosaccharide on cytokine secretions by porcine alveolar macrophages and serum cytokine concentrations in nursery pigs

This study explored the hypothesis that mannan oligosaccharide (MOS) acts to reduce systemic inflammation in pigs by evaluating cytokine production of alveolar macrophages (AM) and serum cytokine concentrations. A total of 160 pigs were fed diets containing 0.2 or 0.4% MOS for 2 or 4 wk postweaning compared with control diets without MOS. Dietary MOS did not affect the serum concentration of tumor necrosis factor (TNF)-α and tended (P = 0.081) to increase that of IL-10. These cytokine concentrations also changed over time (P < 0.001). After 2-wk feeding of the control or MOS diets, AM were collected and stimulated ex vivo with lipopolysaccharide (LPS) or polyinosinic:polycytidylic acid (PLIC) as infection models. The LPS-stimulated AM from MOS-fed pigs (n = 12) secreted less TNF-α (P < 0.001) and more IL-10 (P = 0.026) than those from control-fed pigs (n = 6). However, dietary MOS had less effect on ex vivo TNF-α and IL-10 production by PLIC-stimulated AM (P = 0.091 and P > 0.10, respectively. Further, effects of MOS were examined in 4 in vitro experiments. In Exp. 1 (n = 4 pigs), MOS and mannan-rich fraction (MRF), when added to AM cultures, were able to increase TNF-α production. This direct effect of MOS was not due to endotoxin contamination as verified in Exp. 2 (n = 6 pigs) using polymyxin B, an inhibitor of LPS activation of toll-like receptor 4. Polymyxin B inhibited production of TNF-α by AM after treatment with LPS (P < 0.001), but not after treatment with MOS in the absence of LPS (P > 0.70). In Exp. 3 (n = 6 pigs), when MOS was directly applied in vitro, the pattern of cytokine production by LPS-activated AM was similar to that observed ex vivo, as MOS suppressed LPS-induced TNF-α (P < 0.001) and enhanced LPS-induced IL-10 (P = 0.028). In Exp. 4 (n = 6 pigs), when MRF replaced MOS, AM-produced TNF-α induced by LPS or PLIC was suppressed by MRF (P = 0.015 or P < 0.001, respectively). These data establish that MOS and MRF suppress LPS-induced TNF-α secretions by AM. Generally, the study suggests that MOS may be a potent immunomodulator because it directly activates AM to secrete TNF-α and alters the cytokine responses of bacterial endotoxin-induced AM in both ex vivo and in vitro systems. In particular, feeding MOS to pigs for 2 wk reduces TNF-α and increases IL-10 concentrations after ex vivo treatment of AM with LPS. These immunomodulatory properties of MOS may have important implications for both host defense and avoidance of harmful overstimulation of the immune system.

Maltooligosaccharides from JEG-3 trophoblast-like cells exhibit immunoregulatory properties

PROBLEM

to better understand the immunoregulatory properties of trophoblasts, we have searched for small immunologically active carbohydrates derived from intact trophoblast-like cells.

METHOD OF STUDY

using solid phase extraction coupled with HPLC and mass spectrometry methods, we have characterized a low molecular weight carbohydrate-rich fraction associated with JEG-3 cells. We have also tested the bioactivities of selected authentic oligosaccharides found in the oligosaccharide fraction.

RESULTS

the most abundant components of the low molecular weight carbohydrate-rich fraction were maltotriose and maltotetraose, with detectable amounts of maltopentaose. When authentic maltooligosaccharides were tested using lymphocytes, IL-2 inhibition was observed. This activity was dependent upon the number of saccharide subunits, stereochemistry, and concentration. To further test maltooligosaccharide properties, maltopentose was attached to glass cover slips. Although spontaneous neutrophil motility was observed on unmodified and control surfaces, it was inhibited on maltooligosaccharide-derivatized surfaces.

CONCLUSION

maltooligosaccharides are associated with the trophoblast's surface where they may exhibit immunoregulatory activities.

Specific immune response to HBsAg is enhanced by β-glucan oligosaccharide containing an α-(1→3)-linked bond and biased towards M2/Th2

Vaccination with Hepatitis B surface antigen (HBsAg) is being used to prevent HBV infection. The fact that 10% of vaccinees fail to develop protective antibodies has fostered a large body of research for more effective vaccination strategies. Search for new adjuvant, able to selectively trigger protective antibody production, is one of the most promising approaches. The oligosaccharide beta-(1-->6)-branched beta-(1-->3) glucohexaose is the basic unit of lentinan and several other fungal beta-glucans with immunostimulatory activity. beta-glucans stimulate innate immune response mainly through interaction with myeloid cells (macrophages) and dendritic cells. In this study, the ability of synthetic beta-(1-->6)-branched beta-(1-->3) glucohexaose analogue (beta-glu6) to enhance the immune response to HBsAg has been evaluated. Administration of synthetic beta-glu6 i.p. in BALB/c mice greatly enhanced the mobilisation and maturation of macrophages and dendritic cells to co-administered HBsAg, as compared to the antigen alone. The adjuvant effect of beta-glu6 was evident in the increase of T and B cell activation in response to HBsAg, as judged by the percentage of CD69-positive CD4(+) and CD19(+) lymphocytes in the spleen. beta-glu6 could significantly enhance the number of IL-4-producing cells in response to HBsAg, while it had no effect on the number of IFN-gamma-producing lymphocytes, suggesting a Th2 bias of the immune response. The correlate of protection for HBV vaccination, i.e. the titer of HBsAg-specific antibodies, was greatly enhanced by the use of beta-glu6 as a vaccine adjuvant. The IgG1/IgG2a ratio within the anti-HBsAg antibodies was higher in the mice immunised with HBsAg plus beta-glu6 than receiving HBsAg alone or mice administered HBsAg with Freund's adjuvant, indicating a shift towards a Th2-biased anti-inflammatory protective antibody response.

Sequence analysis of alginate-derived oligosaccharides by negative-ion electrospray tandem mass spectrometry

Negative-ion electrospray tandem mass spectrometry (ES-MS/MS) with collision-induced dissociation (CID) is attempted for sequence determination of alginate oligosaccharides, derived from polyanionic alginic acid, polymannuronate, and polyguluronate by partial depolymerization using either alginate lyase or mild acid hydrolysis. Sixteen homo- and hetero-oligomeric fragments were obtained after fractionation by gel-filtration and strong anion exchange high performance liquid chromatography. The product-ion spectra of these alginate oligosaccharides were dominated by intense B-, C-, Y-, and Z-type ions together with (0,2)A- and (2,5)A-ions of lower intensities. Internal mannuronate residues (M) produce weak but specific decarboxylated Z(int)-ions (Z(int) - 44 Da; int: denotes internal), which can be used for distinction of M and a guluronate residue (G) at an internal position. A reducing terminal M or G, although neither gives rise to a specific ion, can be identified by differences in the intensity ratio of fragment ions of the reducing terminal residue [(2,5)A(red)]/[(0,4)A(red)] (red: denotes reducing terminal).

Cactus stems (Opuntia spp.): A review on their chemistry, technology, and uses

Although traditionally used as a valuable health supporting nutrient, the vegetative parts of Opuntia spp. plants are scarcely used in modern nutrition and medicine. While all kinds of different Opuntia spp. have been studied, a systematic approach regarding the inter-relationships between the composition and the pre- and postharvest conditions is still missing. Therefore, the present review compiles and discusses literature on the chemical composition of cactus stems, the knowledge on uses in food, medicine, and cosmetics. It is concluded that much research is needed to get an insight into the multitude of bioactivities reported in the traditional literature but also to take advantage of the respective constituents for food and pharmaceutical applications.