Effect and Tolerability of a Nutritional Supplement Based on a Synergistic Combination of ß-Glucans and Selenium- and Zinc-Enriched Saccharomyces cerevisiae (ABB C1®) in Volunteers Receiving the Influenza or the COVID-19 Vaccine: A Randomized, Double-Blind, Placebo-Controlled Study.

A single-center, randomized, double-blind, placebo-controlled study was conducted in 72 volunteers who received a synergistic combination of yeast-based ingredients with a unique ß-1,3/1,6-glucan complex and a consortium of heat-treated probiotic Saccharomyces cerevisiae rich in selenium and zinc (ABB C1®) or placebo on the next day after getting vaccinated against influenza (Chiromas®) (n = 34) or the COVID-19 (Comirnaty®) (n = 38). The duration of treatment was 30 and 35 days for the influenza and COVID-19 vaccine groups, respectively. Mean levels of CD4+T cells increased from 910.7 at baseline to 1000.2 cells/µL after the second dose of the COVID-19 vaccine in the ABB C1® group, whereas there was a decrease from 1055.1 to 929.8 cells/µL in the placebo group. Changes of CD3+T and CD8+T lymphocytes showed a similar trend. In the COVID-19 cohort, the increases in both IgG and IgM were higher in the ABB C1® supplement than in the placebo group. Serum levels of selenium and zinc showed a higher increase in subjects treated with the active product than in those receiving placebo. No serious adverse events related to ABB C1® or tolerance issues were reported. The study findings validate the capacity of the ABB C1® product to stimulate trained immunity.

Immunomodulating Effects of Fungal Beta-Glucans: From Traditional Use to Medicine.

The importance of a well-functioning and balanced immune system has become more apparent in recent decades. Various elements have however not yet been uncovered as shown, for example, in the uncertainty on immune system responses to COVID-19. Fungal beta-glucans are bioactive molecules with immunomodulating properties. Insights into the effects and function of beta-glucans, which have been used in traditional Chinese medicine for centuries, advances with the help of modern immunological and biotechnological methods. However, it is still unclear into which area beta-glucans fit best: supplements or medicine? This review has highlighted the potential application of fungal beta-glucans in nutrition and medicine, reviewing their formulation, efficacy, safety profile, and immunomodulating effects. The current status of dietary fungal glucans with respect to the European scientific requirements for health claims related to the immune system and defense against pathogens has been reviewed. Comparing the evidence base of the putative health effects of fungal beta-glucan supplements with the published guidance documents by EFSA on substantiating immune stimulation and pathogen defense by food products shows that fungal beta-glucans could play a role in supporting and maintaining health and, thus, can be seen as a good health-promoting substance from food, which could mean that this effect may also be claimed if approved. In addition to these developments related to food uses of beta-glucan-containing supplements, beta-glucans could also hold a novel position in Western medicine as the concept of trained immunity is relatively new and has not been investigated to a large extent. These innovative concepts, together with the emerging success of modern immunological and biotechnological methods, suggest that fungal glucans may play a promising role in both perspectives, and that there are possibilities for traditional medicine to provide an immunological application in both medicine and nutrition.

Fungal beta-glucans as adjuvants for treating cancer patients - A systematic review of clinical trials.

BACKGROUND & AIMS: Fungal ß-glucans have been considered as biological response modifiers (BRMs) promoting stimulation of immune system according to numerous scientific publications performed in vitro and in vivo. Some clinical trials involving such compounds started to be published since 1980's. This systematic review aimed to compile and compare clinical studies using these ß-glucans as adjuvants on patients undergoing cancer treatment. Healthy subjects and ß-glucans from other sources were excluded. METHODS: It was developed according to PRISMA-P guidelines (PROSPERO registered n. CRD42020151539), using PICO criteria and the following databases: PubMed, Scielo and LILACS. RESULTS: We found 1018 articles and after removing duplicated records, select by title/abstract and full-text, only 9 studies remained and 7 more were manually added, totalizing 16 trials involving 1650 patients, with arm sizes varying from 9 until 200 patients. The selected studies (published since 1992-2018) included subjects with diagnosis of 9 types of cancer. The studies used different sources of ß-glucans, such as yeast (Saccharomyces cerevisiae), mushrooms (Lentinula edodes and Schizophyllum commune) and non-described fungal sources. CONCLUSIONS: It was observed that the administration of ß-glucan is safe and well-tolerated. Most of the trials pointed that concomitant administration of ß-glucan with chemo or radiotherapy reduced the immune depression caused by such treatments and/or accelerated the recovery of white blood cells counts. However, some articles also commented that no statistical difference was encountered between ß-glucan treated vs. control groups, which gives a controversial conclusion about the ß-glucan effects. The great diversity among the methodology studies and insufficient information was an impeditive for achieving profound statistical analysis, therefore a narrative report of the included studies was performed indicating that further evidences are required to determine the efficacy of this adjuvant in the cancer treatment.

Functional activities of beta-glucans in the prevention or treatment of cervical cancer.

Cervical cancer is the fourth-ranked cancer in the world and is associated with a large number of deaths annually. Chemotherapy and radiotherapy are known as the common therapeutic approaches in the treatment of cervical cancer, but because of their side effects and toxicity, researchers are trying to discovery alternative therapies. Beta-glucans, a group of glucose polymers that are derived from the cell wall of fungi, bacteria, and etc. it has been showed that beta-glucans have some anti-cancer properties which due to their impacts on adaptive and innate immunity. Along to these impacts, these molecules could be used as drug carriers. In this regard, the application of beta-glucans is a promising therapeutic option for the cancer prevention and treatment especially for cervical cancer. Herein, we have summarized the therapeutic potential of beta-glucans alone or as adjuvant therapy in the treatment of cervical cancer. Moreover, we highlighted beta-glucans as drug carriers for preventive and therapeutic purposes.

Enhancement of adaptive immune responses of aged mice by dietary intake of ß-glucans, with special emphasis on anti-aging activity.

The naturally occurring polysaccharide, ß-1,3-glucans, a well-known immunostimulant, has been highly valued for many years for their health-promoting and anti-aging properties, but its mode of action is poorly understood. In this study, we first showed that oral administration of ß-1,3-glucans did not affect the general condition and physiology of male mice throughout the trial period. We then showed that dietary intake of ß-1,3-glucans induced a significant increase in T helper cells (CD4+) in young, middle-aged and aged male mice. We also showed that ß-1,3-glucans supplementation considerably increased the delayed-type hypersensitivity (DTH) response, a T cell-mediated immune response, in young and aged mice. In addition, we found that ß-1,3-glucans supplementation remarkably promoted the production of total anti-keyhole limpet hemocyanin (KLH) immunoglobulin G (IgG), anti-KLH IgG1, and anti-KLH IgG2a in young and aged mice without disturbing immune homeostasis. These data together indicate that oral administration of ß-1,3-glucans enhanced the adaptive immune responses of aged mice without disturbing their general condition and physiology, supporting the idea that ß-1,3-glucans are capable of counteracting the immunosenescence in mice. They also suggest that ß-1,3-glucans can be clinically useful to help the elderly generate an improved response to vaccine with stronger humoral and cell-mediated immune responses.

Yeast-Derived ß-Glucan in Cancer: Novel Uses of a Traditional Therapeutic.

An increased understanding of the complex mechanisms at play within the tumor microenvironment (TME) has emphasized the need for the development of strategies that target immune cells within the TME. Therapeutics that render the TME immune-reactive have a vast potential for establishing effective cancer interventions. One such intervention is ß-glucan, a natural compound with immune-stimulatory and immunomodulatory potential that has long been considered an important anti-cancer therapeutic. ß-glucan has the ability to modulate the TME both by bridging the innate and adaptive arms of the immune system and by modulating the phenotype of immune-suppressive cells to be immune-stimulatory. New roles for ß-glucan in cancer therapy are also emerging through an evolving understanding that ß-glucan is involved in a concept called trained immunity, where innate cells take on memory phenotypes. Additionally, the hollow structure of particulate ß-glucan has recently been harnessed to utilize particulate ß-glucan as a delivery vesicle. These new concepts, along with the emerging success of combinatorial approaches to cancer treatment involving ß-glucan, suggest that ß-glucan may play an essential role in future strategies to prevent and inhibit tumor growth. This review emphasizes the various characteristics of ß-glucan, with an emphasis on fungal ß-glucan, and highlights novel approaches of ß-glucan in cancer therapy.

Effects of oral butyrate supplementation on inflammatory potential of circulating peripheral blood mononuclear cells in healthy and obese males.

Sodium butyrate is well-known for its immune-modulatory properties. Studies until now only focused on the in vitro effects of butyrate or assessed local effects in the gut upon butyrate administration. In this trial, we studied the systemic anti-inflammatory effects induced by sodium butyrate supplementation in humans. Nine healthy (Lean) and ten obese (metabolic syndrome group, MetSyn) males were given 4 grams sodium butyrate daily for 4 weeks. PBMCs were isolated before and after supplementation for direct stimulation experiments and induction of trained immunity by oxidized low-density lipoprotein (oxLDL), ß-glucan, or Bacillus Calmette-Guérin vaccine (BCG). Butyrate supplementation moderately affected some of the cytokine responses in the MetSyn group. In the direct stimulation setup, effects of butyrate supplementation were limited. Interestingly, butyrate supplementation decreased oxLDL-induced trained immunity in the MetSyn group for LPS-induced IL-6 responses and Pam3CSK4-induced TNF-α responses. Induction of trained immunity by ß-glucan was decreased by butyrate in the MetSyn group for Pam3CSK4-induced IL-10 production. In this study, while having only limited effects on the direct stimulation of cytokine production, butyrate supplementation significantly affected trained immunity in monocytes of obese individuals with metabolic complications. Therefore, oral butyrate supplementation may be beneficial in reducing the overall inflammatory status of circulating monocytes in patients with metabolic syndrome.

Immunoreactivity of the Cold Water Extract of Royal Sun Culinary-Medicinal Mushroom, Agaricus brasiliensis Strain KA21 (Agaricomycetes), Assessed by Immunoglobulin Preparations for Intravenous Injection.

The royal sun medicinal mushroom, Agaricus brasiliensis, is a health food material that helps to improve quality of life. A. brasiliensis has long been used as a tea by extraction with cold and hot water. Our group has been investigating the immunopharmacological activities of the A. brasiliensis KA21 strain, which is cultivated outdoors. We prepared cold water (AgCWE) and hot water (AgHWE) extracts of this strain. AgCWE contained a larger proportion of proteins, including enzymes, and showed a brownish color during the extraction process. By contrast, chemical and immunochemical analyses revealed that AgHWE contained large amounts of ß-1,3-/1,6-glucans. In an attempt to elucidate the immunochemical characteristics of AgCWE, reactivities to immunoglobulin (Ig) preparations for intravenous injection were analyzed and compared with standard materials. To characterize brownish high-molecular weight components, standard phenol compounds such as caffeic acid (CA), trans-ferulic acid (FA), and coumaric acid (CouA) were polymerized to brownish polymerized polyphenols (PPPs) (i.e., polymerized CA, polymerized FA, and polymerized CouA) by laccase or peroxidase. The results obtained revealed that intravenous Ig reacted with all PPPs and PPPs cross-reacted with AgCWE and AgHWE. The isotype of the anti-PPP antibody was found to be IgG1, in contrast to that of the ß-glucan antibody, which was mainly IgG2. These results strongly suggest that A. brasiliensis extracts contain immunoreactive components against various classes of Igs.

Effect of dietary ß-glucan on growth, survival and regulation of immune processes in rainbow trout (Oncorhynchus mykiss) infected by Aeromonas salmonicida.

The present study evaluated the effects of dietary ß-glucan (0, 0.05%, 0.1%, and 0.2%) on growth performance after 42 days of feeding. Thereafter, rainbow trout (Oncorhynchus mykiss) were infected with Aeromonas salmonicida, and survival rates as well as the regulating processes of stress- and immune-related factors were analyzed. In general, higher dietary ß-glucan levels obviously improved specific growth rate (SGR), weight gain (WG) and feed efficiency (FE) (P ≤ 0.05). Survival rates in ß-glucan groups increased significantly compared with the control group after A. salmonicida infection (P ≤ 0.05). Serum total superoxide dimutase (T-SOD), peroxidase (POD) as well as catalase (CAT) activities, and their mRNA expressions in the head kidney of fish in the ß-glucan groups generally increased to higher levels after infection, and more quickly, compared with in the control group. Serum lysozyme (LSZ) and its expression in the head kidney in ß-glucan groups reached a higher peak earlier than in the control group. Serum glutamic oxalacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels in the ß-glucan groups were significantly lower than in the control group (P ≤ 0.05). The peak of heat shock protein 70 (HSP70) expression in the 0.2% ß-glucan group was higher and occurred earlier than in other groups (P ≤ 0.05). These results confirm that 0.1% and 0.2% dietary ß-glucan are beneficial for promoting growth in rainbow trout and enhancing resistance against A. salmonicida. Furthermore, ß-glucan could play an important role in regulating stress- and immune-related factors in rainbow trout to more quickly fight against bacterial infection.

Feeding of nano scale oats ß-glucan enhances the host resistance against Edwardsiella tarda and protective immune modulation in zebrafish larvae.

In this study, we prepared and characterized the oats origin of nano scale ß-glucan (NBG) and investigated the immunomodulatory properties in zebrafish larvae. Newly prepared NBG (average particle size of 465 nm) was fully soluble in water. Zebrafish larvae survival rate was increased against pathogenic bacteria Edwardsiella tarda, when NBG was added to the water (500 µg/mL) compared to NBG non-exposed controls. Moreover, quantitative real time PCR (qRT-PCR) results showed up-regulation of immune functional genes including TNF-α, IL-1ß, ß-defensin, lysozyme, IL 10, IL 12 and C-Rel indicating higher survival rate could be due to stronger immunomodulatory function of NBG (500 µg/mL). Thus, non-toxic, water soluble and biodegradable NBG from oats could be considered as the potential immunostimulant for larval aquaculture.

Immunochemical Cross-Reactivity of ß-Glucan in the Medicinal Plant, Sasa veitchii (Japanese Folk Medicine Kumazasa), and Medicinal Mushrooms.

Fungal ß-glucan is a representative pathogen-associated molecular pattern from mushroom, yeast, and fungi and stimulates innate as well as acquired immune systems. This ß-glucan is widely applied in functional food to enhance immunity. Humans and animals generally become sensitized to this ß-glucan and gradually produce specific antibodies to ß-glucans. The extracts of plants have been used as folk medicine and are reported to possess various biological activities that are beneficial for human health, such as antitumor, antiallergic, and anti-inflammatory activities. In the present study, the immunochemical cross-reactivity of Sasa extract and fungal ß-glucan was analyzed. We found that the anti-ß-glucan antibody in human sera strongly cross-reacted with the Sasa extract. This result strongly suggested that plant extracts modulate the immunostimulating effects of medicinal mushrooms. The cooperative effects of plants and mushrooms may be an important issue for functional foods.

Allergen-Associated Immunomodulators: Modifying Allergy Outcome.

The prevalence of allergies is increasing since mid twentieth century; however the underlying causes of this increase are not fully clear. Understanding the mechanism by which a harmless protein becomes an allergen provides us with the basis to prevent and treat these diseases. Although most studies on allergen immunogenicity have traditionally focused on structural properties of the proteins, it is increasingly clear that allergenicity cannot be determined only based on structural features of the allergenic proteins. In fact, allergens do not encounter human facings as isolated molecules but contained in complex mixtures of proteins, carbohydrates and lipids, such as pollen grains or foods. As a result, attention has lately been directed to examine whether allergen-associated molecules exhibit immune-regulatory properties. The present review aims to illustrate some examples of how non-protein molecules accompanying the allergen can modulate allergic responses.

Safety and immunogenicity of a soluble native Neospora caninum tachyzoite-extract vaccine formulated with a soy lecithin/ß-glucan adjuvant in pregnant cattle.

The global economic impact of Neospora caninum infection in cattle herds has promoted the development of vaccines that can be safely used during pregnancy. The aim of this study was to evaluate the safety and immunogenicity of a vaccine formulated with the soluble fraction of tachyzoite's lysate and a soy-based aqueous adjuvant (sNcAg/AVEC), which was protective in the mouse model and induced strong IFN-γ responses and high avidity antibodies in non-pregnant cattle. Ten pregnant heifers were vaccinated twice during the first trimester of gestation and 8 remained unvaccinated. Anti-N. caninum immune responses were efficiently primed by vaccination, evidenced by a quick induction of IgM serum titers (7dpv) and a prompt switch to high avidity IgG shortly after infection (performed at 78 or 225 days of gestation; n=5 each); while naïve cattle elicited lower IgG titers, with a delayed kinetics. High systemic IFN-γ levels were induced after infection which did not interfere with pregnancy. No local or systemic adverse effects were recorded along the study. Calves were born in term and in good health conditions, showing that the sNcAg/AVEC vaccine was safe when applied to healthy heifers during the first trimester of gestation.

Innate immunity induced by fungal ß-glucans via dectin-1 signaling pathway.

Mushrooms are a highly valuable source of substances that possess unique biological properties and medicinal efficacy. Medicinal mushrooms traditionally have been used to treat cancer, fungal infections, hypertension, diabetes, inflammation, and renal disorders. Medicinal mushrooms produce high-molecular-weight ß-glucans, which have antitumor and antifungal activities that stimulate innate immunity. Innate immune cells express pattern recognition receptors (PRRs) such as dectin-1, Toll-like receptors, and mannose receptors on their cell surfaces. These PRRs recognize pathogens by binding to highly conserved pathogen-associated molecular patterns such as ß-glucan, mannan, and lipopolysaccharide. The immunomodulating activities of innate immune cells are augmented by the binding of ß-glucans to dectin-1 that is expressed by macrophages or dendritic cells. Upon binding ß-glucan, innate immune cells activate adaptive immune cells such as B and T lymphocytes or natural killer cells by secreting various cytokines such as interleukins (IL-4, IL-6) and tumor necrosis factor-α. Water-insoluble ß-glucans have stronger immunostimulating activities than their water-soluble counterparts. ß-glucans have antifungal activity that is similar to their anticancer activities and is mediated by binding to dectin-1, albeit by an unknown mechanism. In this review we discuss recent progress in understanding the mechanisms responsible for the antitumor activities of fungal ß-glucans that act through pathogen-associated molecular patterns and PRRs.

Curdlan ß-1,3-glucooligosaccharides induce the defense responses against Phytophthora infestans infection of potato (Solanum tuberosum L. cv. McCain G1) leaf cells.

Activation of the innate immune system before the invasion of pathogens is a promising way to improve the resistance of plant against infection while reducing the use of agricultural chemicals. Although several elicitors were used to induce the resistance of potato plant to microbial pathogen infection, the role of curdlan oligosaccharide (CurdO) has not been established. In the current study, the defense responses were investigated at biochemical and proteomic levels to elucidate the elicitation effect of CurdOs in foliar tissues of potato (Solanum tuberosum L. cv. McCain G1). The results indicate that the CurdOs exhibit activation effect on the early- and late-defense responses in potato leaves. In addition, glucopentaose was proved to be the shortest active curdlan molecule based on the accumulation of H2O2 and salicylic acid and the activities of phenylalanine amino-lyase, ß-1,3-glucanase and chitinase. The 2D-PAGE analysis reveals that CurdOs activate the integrated response reactions in potato cells, as a number of proteins with various functions are up-regulated including disease/defense, metabolism, transcription, and cell structure. The pathogenesis assay shows that the ratio of lesion area of potato leaf decreased from 15.82%±5.44% to 7.79%±3.03% when the plants were treated with CurdOs 1 day before the infection of Phytophthora infestans. Furthermore, the results on potato yield and induction reactions indicate that the defense responses induced by CurdOs lasted for short period of time but disappeared gradually.

Effects of ß-glucan on some environmental toxins: An overview.

BACKGROUND: Beta-glucans are naturally occurring polysaccharides and constituents of the cell wall of certain pathogenic bacteria and fungi. They have proven healing and immunostimulating properties, linked to enhanced macrophage and natural killer cell function which likely involves specific interaction with several cell surface receptors, such as lactosylceramide, selected scavenger receptors, and dectin-1 (betaGR). In particular, glucan reduces the immunosuppressive effects of a number of agents including chemo therapy and radiation. More recent studies suggest a positive function for glucan in the immunosuppression caused by toxic agents in the environment. AIM: An overview of the effects of glucan on the mycotoxin, aflotoxin and other environmental toxins (mercury-thimerosal, depleted uranium). CONCLUSION: Glucan is effective as a natural immunomodulator and could be used as an inexpensive solution to reducing the adverse effects of some environmental toxins.

ß-Glucan-supplemented diets increase poly(I:C)-induced gene expression of Mx, possibly via Tlr3-mediated recognition mechanism in common carp (Cyprinus carpio).

We have previously observed that in common carp (Cyprinus carpio), administration of ß-glucan (MacroGard®) as feed additive leads to a lower expression of pro-inflammatory cytokines suggesting that this immunostimulant may be preventing an acute and potentially dangerous response to infection, particularly in the gut. However, in general, mechanisms to detect and eliminate pathogens must also be induced in order to achieve an efficient clearance of the infection. Protection against viral diseases acquired through ß-glucan-supplemented feed has been extensively reported for several experimental models in fish but the underlining mechanisms are still unknown. Thus, in order to better characterize the antiviral action induced by ß-glucans in fish, MacroGard® was administered daily to common carp in the form of supplemented commercial food pellets. Carp were fed for a period of 25 days prior to intra-peritoneal injection with polyinosinic:polycytidylic acid (poly(I:C)), a well-known double-stranded RNA mimic that triggers a type-I interferon (IFN) response. Subsequently, a set of immune related genes, including mx, were analysed by real-time PCR on liver, spleen, head kidney and mid gut tissues. Results obtained confirmed that treatment with ß-glucan alone generally down-regulated the mRNA expression of selected cytokines when compared to untreated fish, while mx gene expression remained stable or was slightly up-regulated. Injection with poly(I:C) induced a similar down-regulated gene expression pattern for cytokines in samples from ß-glucan fed fish. In contrast, poly(I:C) injection markedly increased mx gene expression in samples from ß-glucan fed fish but hardly in samples from fish fed control feed. In an attempt to explain the high induction of mx, we studied Toll-like receptor 3 (TLR3) gene expression in these carp. TLR3 is a prototypical pattern recognition receptor considered important for the binding of viral double-stranded RNA and triggering of a type-I IFN response. Through genome data mining, two sequences for carp tlr3 were retrieved (tlr3.1 and tlr3.2) and characterized. Constitutive gene expression of both tlr3.1 and tlr3.2 was detected by real-time PCR in cDNA of all analysed carp organs. Strikingly, 25 days after ß-glucan feeding, very high levels of tlr3.1 gene expression were observed in all analysed organs, with the exception of the liver. Our data suggest that ß-glucan-mediated protection against viral diseases could be due to an increased Tlr3-mediated recognition of ligands, resulting in an increased antiviral activity of Mx.

Analysis of the titer and reactivity of antibody/ies against fungal cell wall ß-glucans in human sera.

The aim of this work was to characterize an antibody response to ß-glucan (BG), a major component of the fungal cell wall, at each isotype in human sera. The titer and reactivity of the anti-human BG antibody were examined using enzyme-linked immunosorbant assay plates coated with Candida soluble cell wall ß-glucan as a standard antigen. The antibody was detected using anti-human immunoglobulin (Ig) G, IgM, and IgA. Its major class was IgG in all subjects. The antibody titer varied significantly. The anti-BG antibody showed greater reactivity to ß-glucans derived from pathogenic fungi than monoglycosyl-branched ß-glucans derived from mycelia culture medium. In addition, it was suggested that the anti-BG IgM antibody was bound relatively strongly to the ß1,3-glucan backbone and the anti-BG IgG antibody to ß1,6-glucan. The anti-BG antibody plays a variety of roles, according to class, in the host's response to fungi. We propose a new index of human response to ß-glucan that effects the understanding of the response to ß-glucan in humans.

Innate immune responses and efficacy of using mushroom beta-glucan mixture (MBG) on orange-spotted grouper, Epinephelus coioides, aquaculture.

This study attempts to describe the effects of innate immunity responses and field application of mushroom beta-glucan mixture (MBG) in cultured orange-sported grouper, Epinephelus coioides. Chemical analysis for MBG showed that the mixture contains 34.06% of macro-molecular polymers with bio-active linkage such as 3-; 3,4- and 4,6-glucopyranosyl and 6-linked galactopyranosyl residues. Study performed on the innate immunity showed that oral ingestion of MBG at 1.0 g and 2.0 g per kilogram of feed levels may significantly enhance the lysozyme activity, alternative complement activity, phagocytic activity and respiration burst of the experimental groupers. Observation on the experimental challenge of pathogen showed that uses of MBG at 0.1% and 0.2% levels in feed might significantly enhance the protection of grouper against Vibrio alginolyticus. Field trials performed on short and long-term culture showed that feeding of diet containing 0.1% or 0.2% of MBG may significantly enhance the survival of cultured groupers up to 16% when compared with those obtained from controls.

Structures of (1→6)-ß-D-glucans from Bulgaria inquinans (Fries) and their immunological activities.

In previous study, an unbranched (1→6)-ß-D-glucan with Mw 2.6kDa was isolated from fruit bodies of Bulgaria inquinans (Fries). In present paper, three branched (1→6)-ß-D-glucans were obtained from the water-extracted residues by a sequential KOH-extraction, namely BIK2, BIK10 and BIK30. Their molecular weights were determined to be 37.5kDa (BIK2), 288.9kDa (BIK10) and 175.5kDa (BIK30). Structural analysis indicated that their backbones were substituted by single glucosyls at C-3 positions, the branching ratios were 0.01 (BIK2), 0.17 (BIK10), 0.25 (BIK30). Immunological tests showed that all the four ß-D-glucans could significantly increase the ConA or LPS-induced lymphocytes proliferation in vivo. Moreover, branched (1→6)-ß-D-glucans have more significantly lymphocytes proliferation activities than unbranched (1→6)-ß-D-glucan, and the effect of (1→6)-ß-D-glucans on lymphocytes proliferation increases along with molecular weights. The present results well enrich the structure-activity relationships of (1→6)-ß-D-glucan, and indicate (1→6)-ß-D-glucans from B. inquinans (Fries) are potential immunostimulating agents.