Geir Hetland

Effects of the Medicinal Mushroom Agaricus blazei Murill on Immunity, Infection and Cancer

Agaricus blazei Murill (AbM) is an edible, medicinal mushroom of Brazilian origin. It is used traditionally against a range of diseases, including cancer and chronic hepatitis, and has been cultivated commercially for the health food market. AbM has recently been shown to have strong immunomodulating properties, which has led to increasing scientific interest. In this article, we review current knowledge as to the immunological properties of AbM, and its possible clinical use in connection with infections and cancer. We also present some novel findings, which point to highly different biological potency between AbM extracts of different source and manufacturing.

An extract of the mushroom Agaricus blazei Murill administered orally protects against systemic Streptococcus pneumoniae infection in mice.

The aim was to investigate the antibacterial effect of the biologically active and edible mushroom Agaricus blazei Murill (AbM). A water extract of AbM or PBS control was administered orally before or with challenge to NIH/OlaHsd mice, experimentally infected intraperitoneally with the moderately virulent Streptococcus pneumoniae serotype 6B. End points were bacteraemia and survival rate. The AbM extract, protected against systemic S. pneumoniae 6B infection in the mice. It was most effective when given 24 h before inoculation but did also have protective effects when given together with challenge compared with control. The lack of antibiotic effect on pneumococci in vitro and increased levels of cytokines MIP‐2 and TNF‐α in the serum of mice receiving AbM extract, indicated that the protective effect of AbM was due to the involvement of the native immune system. This is the first report of anti‐infection effects of AbM in vivo. Our results suggest that AbM extract may be useful as additional prophylactic and possibly therapeutic treatment against bacterial and possibly other infections in humans.

Effect of an Extract Based on the Medicinal Mushroom Agaricus blazei Murill on Release of Cytokines, Chemokines and Leukocyte Growth Factors in Human Blood Ex Vivo and In Vivo

An immunostimulatory extract based on the medicinal mushroom Agaricus blazei Murill (AbM) has been shown to stimulate mononuclear phagocytes in vitro to produce pro‐inflammatory cytokines, and to protect against lethal peritonitis in mice. The present aim was to study the effect of AbM on release of several cytokines in human whole blood both after stimulation ex vivo and in vivo after oral intake over several days in healthy volunteers. The 17 signal substances examined were; T helper 1 (Th1) cytokines [interleukin (IL)‐2, interferon (IFN)‐γ and IL‐12], T helper 2 cytokines (IL‐4, IL‐5 and IL‐13), pleiotropic (IL‐7, IL‐17), pro‐inflammatory [IL‐1β, IL‐6, tumour necrosis factor (TNF)‐α (mainly produced by Th1 cells)] – and anti‐inflammatory (IL‐10) cytokines, chemokines [IL‐8, macrophage inhibitory protein (MIP)‐1β and monocyte chemoattractant protein (MCP)‐1] and leukocyte growth factors [granulocyte colony‐stimulating factor (G‐CSF), granulocyte/macrophage colony stimulating factor]. After stimulation of whole blood ex vivo with 0.5–5.0% of a mushroom extract, AndoSan™ mainly containing AbM, there was a dose‐dependent increase in all the cytokines studied, ranging from two to 399‐fold (TNF‐α). However, in vivo in the eight volunteers who completed the daily intake (60 ml) of this AbM extract for 12 days, a significant reduction was observed in levels of IL‐1β (97%), TNF‐α (84%), IL‐17 (50%) and IL‐2 (46%). Although not significant, there was a trend towards reduced levels for IL‐8, IFN‐γ and G‐CSF, whilst those of the remaining nine cytokines tested, were unaltered. The discrepant results on cytokine release ex vivo and in vivo may partly be explained by the antioxidant activity of AbM in vivo and limited absorption of its large, complex and bioactive β‐glucans across the intestinal mucosa to the reticuloendothelial system and blood.

Protective Effect of Plantago major L. Pectin Polysaccharide against Systemic Streptococcus pneumoniae Infection in Mice

The antibacterial effect of a soluble pectin polysaccharide, PMII, isolated from the leaves of Plantago major, was examined in inbred NIH/OlaHsd and Fox Chase SCID mice experimentally infected with Streptococcus pneumoniae serotype 6B. Serotype 6B is known to give a more protracted infection when injected intraperitoneally into susceptible mice than more virulent serotypes like type 4. PMII was administered i.p. either once 3 days before challenge or once to thrice from 3 to 48 h after challenge. The number of bacteria in blood and the mouse survival rate were recorded. Pre‐challenge administration of PMII and also lipopolysaccharide (LPS), included as a control, gave a dose‐dependent protective effect against S. pneumoniae type 6B infection. However, injection of PMII after establishment of the infection in NIH/OlaHsd mice had no effect. The data demonstrate that, firstly, the polysaccharide fraction PMII from P. major protects against pneumococcal infection in mice when administered systemically prechallenge, and secondly that the protective effect is owing to stimulation of the innate and not the adaptive immune system.

The fungal cell wall component β-1,3-glucan has an adjuvant effect on the allergic response to ovalbumin in mice.

The polyglucose beta-1,3-D-glucan is a major structural component of the cell wall of yeasts and fungi. In the present study, the adjuvant activity of beta-1,3-glucan from the fungus Sclerotinia sclerotiorum (SSG) on the response to the model allergen ovalbumin (OA) was studied, using the popliteal lymph node assay (PLNA) in BALB/c mice. The adjuvant activity on the local cellular response was determined by measuring the weight, cell number, and proliferation of the extracted PLNs. The levels of OA-specific immunoglobulin (Ig)E, IgG1, and IgG2a in serum were measured by enzyme-linked immunosorbent assay (ELISA). Groups of 8 mice were given either SSG + OA, SSG alone, or OA alone on d 0. Thereafter they were exsanguinated on d 20, or reinjected with OA on d 21, before exsanguination on d 26 or 33. Only on d 26 was SSG + OA found to significantly increase the PLN weight and cell numbers, but not cell proliferation (thymidine incorporation), compared with OA or SSG alone. SSG + OA was also found to significantly increase both the anti-OA IgE and IgG1 levels on d 20, 26, and 33 compared to OA alone. Compared to SSG alone, SSG + OA increased the OA-specific IgE and IgG 1 levels significantly on d 26 and 33, but not on d 20. A similar increase was not found for IgG2a. Our results show that beta-1,3-D-glucan provides a clear Th2-dependent (allergic) immune response to OA, indicated by elevated levels of IgE and IgG1 and not IgG2a, in the mouse model used.

An Extract of the Medicinal Mushroom Agaricus blazei Murill Differentially Stimulates Production of Pro-inflammatory Cytokines in Human Monocytes and Human Vein Endothelial Cells in vitro

An extract of the edible mushroom Agaricus blazei Murill (AbM) has known antitumor and anti-infection properties, probably mainly by stimulating mononuclear phagocytes of the native immune system. The aim of this work was to study the effect of AbM on the production by human monocytes and human umbilical vein endothelial cells (EC) of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, TNFα), the anti-inflammatory/T regulatory cytokine IL-10 and the pro-Th1 cytokine IL-12. AbM, in concentrations from 1–15%, induced a considerable and dose-dependent increase in production of IL-8, IL-6, TNFα and IL-1β in monocyte cultures. The biosynthesis reached a plateau at a concentration of 10% of AbM, and was most pronounced for the three former cytokines. AbM did also dose-dependently stimulate EC production of IL-8,IL-6 and TNFα, but at lower levels compared with the monocytes. AbM did neither induce synthesis of cytokines IL-10 nor IL-12 in monocytes or EC. Our results demonstrate the differential effect of AbM stimulation on the magnitude of pro-inflammatory cytokines produced by monocytes and EC.

An extract of the medicinal mushroom Agaricus blazei Murill can protect against allergy

BackgroundAgaricus blazei Murill (AbM) is an edible Brazilian mushroom that has been used in traditional medicine for a range of diseases. It has been shown to have anti-infection and anti-tumor properties in the mouse, which are due to induction of Th1 responses. On the other hand, IgE-mediated allergy is induced by a Th2 response.ObjectiveSince according to the Th1/Th2 paradigm an increased Th1 response may promote a reduced Th2 response, the aim was to examine whether AbM had anti-allergy effects.MethodsA mouse model for allergy was employed, in which the mice were immunized s.c. with the model allergen ovalbumin (OVA). Additionally, the animals were given a mushroom extract, AndoSan™, mainly (82%) containing AbM, but also Hericium erinaceum (15%) and Grifola frondosa (3%), or PBS p.o. either a day before or 19 days after the immunization. The mice were sacrificed on day 26, and anti-OVA IgE (Th2 response) and IgG2a (Th1 response) antibodies were examined in serum and Th1, Th2 and Treg cytokines in spleen cells cultures.ResultsIt was found that the AndoSan™ extract both when given either before or after OVA immunization reduced the levels of anti-OVA IgE, but not IgG2a, in the mice. There was a tendency to reduced Th2 relative to Th1 cytokine levels in the AndoSan™ groups.ConclusionThis particular AbM extract may both prevent allergy development and be used as a therapeutical substance against established allergy.

AN EXTRACT OF THE MUSHROOM AGARICUS BLAZEI MURILL PROTECTS AGAINST LETHAL SEPTICEMIA IN A MOUSE MODEL OF FECAL PERITONITIS

ABSTRACT Bacterial septicemia is frequently occurring during gastroenterological surgery. Because of increasing problems in hospitals with bacteria developing multiresistance against antibiotics, prophylactic treatment using immunomodulators is interesting. We have examined the putatively anti-infective immunomodulatory action of the edible mushroom, Agaricus blazei Murill (AbM), in an experimental peritonitis model in BALB/c mice. The mice were orally given an extract of AbM or phosphate-buffered saline 1 day before the induction of peritonitis with various concentrations of feces from the mice. The state of septicemia, as measured by the number of colony-forming units of bacteria in blood, and the survival rate of the animals were compared between the groups. Mice that were orally treated with AbM extract before bacterial challenge showed significantly lower levels of septicemia and improved survival rates. Our findings suggest that the AbM extract, when given prophylactically, may improve health. Further studies are needed on humans when considering whether AbM could be used as an alternative treatment modality for patients at risk of contracting serious bacterial peritonitis.

Effect of an Extract Based on the Medicinal Mushroom Agaricus blazei Murill on Expression of Cytokines and Calprotectin in Patients with Ulcerative Colitis and Crohn's disease

An immunomodulatory extract (AndoSan™) based on the medicinal mushroom Agaricus blazei Murill (AbM) has shown to reduce blood cytokine levels in healthy volunteers after 12 days’ ingestion, pointing to an anti‐inflammatory effect. The aim was to study whether AndoSan™ had similar effects on cytokines in patients with ulcerative colitis (UC) and Crohn’s disease (CD). Calprotectin, a marker for inflammatory bowel disease (IBD), was also measured. Patients with CD (n = 11) and with UC (n = 10) consumed 60 ml/day of AndoSan™. Patient blood plasma was harvested before and after 6 h LPS (1 ng/ml) stimulation ex vivo. Plasma and faecal calprotectin levels were analysed using ELISA and 17 cytokines [IL‐2, IFN‐γ, IL‐12 (Th1), IL‐4, IL‐5, IL‐13 (Th2), IL‐7, IL‐17, IL‐1β, IL‐6, TNF‐α, IL‐8, MIP‐1β, MCP‐1, G‐CSF, GM‐CSF and IL‐10] by multiplex assay. After 12 days’ ingestion of AndoSan™, baseline plasma cytokine levels in UC was reduced for MCP‐1 (40%) and in LPS‐stimulated blood for MIP‐1β (78%), IL‐6 (44%), IL‐1β (41%), IL‐8 (30%), G‐CSF (29%), MCP‐1 (18%) and GM‐CSF (17%). There were corresponding reductions in CD: IL‐2 (100%), IL‐17 (55%) and IL‐8 (29%) and for IL‐1β (35%), MIP‐1β (30%), MCP‐1 (22%), IL‐8 (18%), IL‐17 (17%) and G‐CSF (14%), respectively. Baseline concentrations for the 17 cytokines in the UC and CD patient groups were largely similar. Faecal calprotectin was reduced in the UC group. Ingestion of an AbM‐based medicinal mushroom by patients with IBD resulted in interesting anti‐inflammatory effects as demonstrated by declined levels of pathogenic cytokines in blood and calprotectin in faeces.

An extract based on the medicinal mushroom Agaricus blazei Murill stimulates monocyte-derived dendritic cells to cytokine and chemokine production in vitro.

The edible mushroom Agaricus blazei Murill (AbM), which has been used in traditional medicine against a range of diseases and possess immunomodulating properties, probably due to its high content of beta-glucans. Others and we have demonstrated stimulatory effects of extracts of this mushroom on different immune cells. Dendritic cells are major directors of immune function. We wanted to examine the effect of AbM stimulation on signal substance release from monocyte-derived dendritic cells (MDDC). After 6d incubation with IL-4 and GM-CSF, the cells were true MDDC. Then the cells were further incubated with up to 10% of the AbM-based extract, AndoSan, LPS (0.5 microg/ml) or PBS control. We found that the AbM extract promoted dose-dependent increased levels of IL-8, G-CSF, TNFalpha, IL-1beta, IL-6 and MIP-1beta, in that order. The synthesis of IL-2, IL-8 and IFNgamma were similar for the AbM extract and LPS. However, AndoSan induced a 10- to 2-fold higher production than did LPS of G-CSF, TNFalpha and IL-1beta, respectively. AbM did not induce increased synthesis of Th2 or anti-inflammatory cytokines or the Th1 cytokine IL-12. We conclude that stimulation of MDDC with an AbM-based extract resulted in increased production of proinflammatory, chemotactic and some Th1-type cytokines in vitro.