Mushrooms & Immune System

Learn how mushrooms stimulate the immune system

Mushrooms Boost the Immune System

More and more people are becoming aware of the fact that mushrooms boost the immune system. But, many of you want to know: how does this process work?

Yes, mushrooms do stimulate our immune system. When a disease-causing pathogen invades our body, the immune system first needs to recognize and differentiate it from our own cells before taking action. To identify non-self molecules, white blood cells in our immune system have receptors that detect foreign structures that do not occur naturally in our body. For instance, humans cannot synthesize beta-glucan carbohydrates; however beta-glucans are a primary component of the cell walls of many fungal and bacterial pathogens. When a cellular receptor detects a beta-glucan, it sends a signal to warn other cells that a pathogen may have entered our system. Defense cell populations are increased, and our immune system prepares for attack. Edible mushrooms, although not harmful to our bodies, contain the same carbohydrates found in many pathogens; eating them has been shown by researchers to stimulate our immune system and increase our ability to fight actual pathogens.

The human immune system has layers of defense. The first line of defense is known as the innate system, and it describes general immunity. Phagocytes including macrophages, neutrophils, and dendritic cells travel through the blood stream and engulf other cells and debris through a process known as phagocytosis. The consumed material is deconstructed by enzymes, and the chemical segments are transferred to the surface of the cell where they can be displayed to other cells. Viruses and other pathogens often have characteristic structures–such as beta-glucans–and the role of phagocytes is to identify these structures and generate antibodies that represent this information. The process of phagocytosis is similar to a neighborhood watch. Citizens in their households are like phagocytes because they keep an eye out for suspicious activity. If a suspicious character is seen breaking into cars, the citizens will call the police with a description of the individual. The description is then used to track the perpetrator to make an arrest. Phagocytes become activated when they encounter suspicious materials and alert the T- and B-cells of the adaptive immune system of their findings. The adaptive system is the body’s second line of defense and like the police, these cells are capable of acting against dangerous pathogens. An active and well-equipped innate system therefore increases pathogen detection and the ability of the body’s second line of defense to act against dangerous non-self cells and viruses.

Because beta-glucans are received as non-self molecules, their impact on the immune system is profound. Scientists at the Medical Institute at Aberdeen University[1] have found that beta-glucans in fungi bind to different phagocytic receptors and trigger the production of innate and adaptive cells, as well as protein messenger molecules, which facilitate communication and biochemical signaling within the immune system. According to an article published in 2009 in the Journal of Microbiology and Biotechnology[2], the beta-glucan lentinan, extracted from shiitake mushrooms, has been shown to increase phagocytic activity, meaning macrophages, neutrophils, and dendritic cells become more active when this beta-glucan is detected. And, according to the article Lentinus Edodes: A Macrofungus with Pharmacological Activities published in 2010 in Current Medicinal Chemistry, lentinan [again, found in shiitake mushrooms] enhanced the host resistance against infections with bacteria, fungi, parasites, and viruses”.

And according to a study published in the International Journal of Biological Macromolecules[3], turkey tail mushrooms have been found to increase respiratory burst, which is a method used by cells in the innate immune system to destroy pathogens by releasing reactive oxygen-based molecules.

If a neighborhood becomes inundated with suspicious-looking individuals, houses will soon be equipped with alarm systems and security lights. In the neighborhood of our immune system, beta-glucans keep act as those alarm systems and security lights, ready to fight off unwanted intruders.

Recent laboratory trials have shown the effectiveness of fungal beta-glucans and terpenoids to bolster the innate immune system[4]. However, despite the vast amount of research occurring, scientists believe there are more mechanisms yet to be fully uncovered. The prospects of future research into the immunomodulating properties of medicinal mushrooms appears promising.

KEY TERMS:

Adaptive Immune System: Contains pathogen-specific receptors that are derived from the antigens presented by the innate system. The adaptive immune system provides a response that is specific to the invading pathogen. In other words, the adaptive system is presented a description of the pathogen and uses this information to look for characteristic structures to find and eliminate the pathogen.

Antigen: A characteristic structure that is used to identify pathogens. Antibodies recognize specific antigens.

B Cell: White blood cells belonging to the adaptive immune system. B cells produce antibodies that recognize characteristic structures of pathogens (antigens). B cells can remember some pathogens for years; this is how vaccines work.

Beta-Glucans: Long chains of glucose (sugar) units with a specific bond orientation. Beta-glucans range in molecular weight, length, and have different branch points. Depending on their characteristics, they have varying effects on the immune system. Humans cannot synthesize beta-glucans.

Cytokines: Are immunomodulating proteins; they send signals and allow cells in the immune system to communicate and carry out tasks in response to information.

Dendritic Cell: Cells that collect and transfer information to other defense cells. When an antigen is detected by dendritic cells, they pass the information on to other cells that will then build immunity and respond accordingly.

Enzyme: Proteins that catalyze reactions by lowering the amount of energy needed for a reaction to occur. If the reactions that take place in our bodies were to be repeated in the laboratory without the use of enzymes, many of them would require extremely high heat (energy). Enzymes are very efficient, produce no waste, and keep us alive.

Immunomodulating: The ability to stimulate the immune system.

Innate Immune System: Defends the body through non-specific actions. The innate immune system recognizes pathogens and activates the adaptive immune system by presenting antigens that describe defining characteristics of the invader.

Macrophage: Are cells that engulf and digest pathogens, cancerous cells, and debris. Macrophages have receptors that bind to proteins and carbohydrates, and they can transmit information received by these receptors to influence the production of cytokines.

Neutrophil: Are the most common white blood cells. They respond to cellular signals from injuries, inflammation, and cancer. Neutrophils are similar to macrophages in that they consume damaged cells.

Non-Self: Any cell or molecule that did not originate in our body.

Pathogen: Is a microorganism or virus that causes disease.

Phagocyte: Engulf both self and non-self cells and debris through a process known as phagocytosis. Phagocytes can kill pathogens by ingesting them, and some can transfer important molecules from the pathogen back to the surface of the cell to display to other cells.

Respiratory Burst: Among other things, a method used for killing pathogens that involves the release of highly-reactive oxygen molecules such as hydrogen peroxide and or nitric oxide.

T Cell: Are white blood cells that have a number of roles in the adaptive immune system. Some remember pathogens for future invasions; some kill pathogens and tumor cells upon stimulus from the innate immune system; some activate other cells and help B cells mature; and others regulate the immune system by suppressing immune response after it is no longer needed.

Terpenoids: Are molecules that are the building blocks for many important biological molecules including all steroids, not just anabolic ones. Terpenoids have been shown to interact with proteins such as those responsible for the replication of HIV.

SELECTED RESEARCH AND HIGHLIGHTS:

Vetvicka, V. (2011). B-Glucan Receptors. Biology and Chemistry of Beta Glucan Vol. 1: Beta Glucans – Mechanisms of Action. (pp. 19-36). Oak Park: Bentham Science Publishers.

“The dative arm of the immune system relies on lymphocytes which recognize antigens from specific pathogens via their antigen receptors with the resultant triggering of clonal expansion, cellular differentiation and the production of specific antibodies.”

“Dectin-1 has been shown to induce a variety of cellular responses following B-glucan recognition including ligand uptake through phagocytosis and endocytosis, the respiratory burst, the production of arachidonic acid metabolites, dendritic cell maturation and the induction of numbers cytokines and chemokines.”

Lee, H., Lee, J., Cho, J., Kim, Y., & Hong, E. (2009). Study on immunostimulating activity of macrophage treated with purified polysaccharides from liquid culture and fruiting body of Lentinus edodes.Journal of microbiology and biotechnology, 19(6), 566-572.

“Phagocytosis is the first step in the macrophages’ response to pathogens. In this process, macrophages will process and present antigens to the lymphocytes by engulfing and digesting the invading pathogens, which in turn elevates the innate immune response.”

“We found that all the polysaccharides increased the phagocytotic uptake of the RAW264.7 cells. In addition, macrophages can defend against pathogen invasion by secreting cytokines, such as the tumor necrosis factor-α (TNF-α), and inflammation mediators such as NO.”

Kang, S., Koo, H., Sohn, E., Park, S., Lim, J., Kim, Y., et al. (2013). Effects of b-glucans from Coriolus versicolor on macrophage phagocytosis are related to the Akt and CK2/Ikaros. International Journal of Biological Macromolecules, 57. Retrieved January 1, 2013, from http://www.ncbi.nlm.nih.gov/pubmed/23500440

“During activation, macrophages undergo induction of phagocytic activity and an increase in the secretion of various materials, such as cytokines and nitric oxide (NO), which bring about nonspecific immune responses. The phagocytic process is initiated by cross-linking of so-called pattern recognition receptors (PRRs), an array of dedicated surface receptors that are capable of innately recognizing non-self structures such as pathogen-associated molecular patterns (PAMPs).”

Akbar, R., & Yam, W. K. (2011). Interaction of ganoderic acid on HIV related target: molecular docking studies. Bioinformation, 7(8), 413-417.

“This study revealed four hydrogen bonds formed between model34 of ganoderic acid B and 1HVR. Hydrogen bonds in 1HVR-Model34 complex were formed through ILE50, ILE50′, ASP29 and ASP30 residues. Interestingly similar interactions were also observed in the native ligand in 1HVR. Furthermore, interactions involving ILE50 and ILE50′ residues have been previously identified to play central roles in HIV-1 protease-ligand interactions. These observed interactions not only suggested HIV-1 protease in general is a suitable target for ganoderic acid B, they also indicated a huge potential for HIV drug discovery based on this compound.”

El-Mekkawy, S., Meselhy, M. R., Nakamura, N., Tezuka, Y., Hattori, M., Kakiuchi, N., et al. (1998). Anti-HIV-1 and anti-HIV-1-protease substances from Ganoderma lucidum. Phytochemistry, 49(6), 1651-1657.

“A new highly oxygenated triterpene named ganoderic acid α has been isolated from a methanol extract of the fruiting bodies of Ganoderma lucidum together with twelve known compounds. The structures of the isolated compounds were determined by spectroscopic means including 2D-NMR. Ganoderiol F and ganodermanontriol were found to be active as anti-HIV-1 agents”

Li, Y., & Wang, S. (2006). Anti-hepatitis B activities of Ganoderic acid from Ganoderma lucidum. Biotechnology Letters, 28(11), 837-841.

“Ganoderic acid, from Ganoderma lucidum, at 8 lg/ml inhibited replication of hepatitis B virus (HBV) in HepG2215 cells over 8 days. Production of HBV surface antigen and HBV e antigen were 20 and 44% of controls without ganoderic acid. Male KM mice were significantly protected from liver injury, induced with carbon tetrachloride, by treatment with ganoderic acid at 10 mg and 30 mg/kgÆd (by intravenous injection) 7 days. Ganoderic acid at the same dosage also significantly protected the mice from liver injury induced by M. bovis BCG plus lipopolysaccharide (from Escherichia coli 0127:B8).”

Bisen, P., Baghel, R., Sanodiya, B., Thakur, G., & Prasad, G. (2010). Lentinus edodes: a macrofungus with pharmacological activities. Current Medicinal Chemistry, 17(22), 2419-2430.

“Lentinan enhanced the host resistance against infections with bacteria, fungi, parasites, and viruses, including the agents of AIDS.  Lentinan reduced the toxicity of azidothymidine AZT (a drug commonly used for treating HIV carriers and AIDS patients). Prevention of the onset of AIDS symptoms through potentiation of host defense is now being actively investigated both experimentally and clinically. In addition to lentinan, other sub- stances from L. edodes have also been shown to have antiviral activity. The mechanism of their effect is in most cases via induction of interferon.”

“Lentinan has also shown: (a) antiviral activity in mice against VSV (vesicular stomatis virus), encephalitis virus, Abelson virus, an adenovirus type 12; (b) stimulated non- specific resistance against respiratory viral infection in mice; (c) conferred complete protection against an LD75 challenge dose of virulent mouse influenza A/SW15; (d) increased resistance to the protozoal parasites Schistosoma japanicum, Sch. mansoni; (e) exhibited activity against Mycobacterium tuberculosis bacilli resistant to antituberculosis drugs, Bacillus subtilis, Staphylococcus aureus, Micrococcus lentos.”

“LEM and a new lignan-rich compound ‘JLS-18’ derived from LEM, blocked the release of infectious Herpes simplex virus in animals.”


[1] Vetvicka, V. (2011). B-Glucan Receptors. Biology and Chemistry of Beta Glucan Vol. 1: Beta Glucans – Mechanisms of Action. (pp. 19-36). Oak Park: Bentham Science Publishers.

[2] Lee, H., Lee, J., Cho, J., Kim, Y., & Hong, E. (2009). Study on immunostimulating activity of macrophage treated with purified polysaccharides from liquid culture and fruiting body of Lentinus edodes. Journal of microbiology and biotechnology, 19(6), 566-572.

[3] Kang, S., Koo, H., Sohn, E., Park, S., Lim, J., Kim, Y., et al. (2013). Effects of b-glucans from Coriolus versicolor on macrophage phagocytosis are related to the Akt and CK2/Ikaros.International Journal of Biological Macromolecules, 57. Retrieved January 1, 2013, from http://www.ncbi.nlm.nih.gov/pubmed/23500440

[4] Akbar, R., & Yam, W. K. (2011). Interaction of ganoderic acid on HIV related target: molecular docking studies. Bioinformation, 7(8), 413-417.

[5] Lee, H., Lee, J., Cho, J., Kim, Y., & Hong, E. (2009). Study on immunostimulating activity of macrophage treated with purified polysaccharides from liquid culture and fruiting body of Lentinus edodes. Journal of microbiology and biotechnology, 19(6), 566-572.

[6] Li, Y., & Wang, S. (2006). Anti-hepatitis B activities of Ganoderic acid from Ganoderma lucidum. Biotechnology Letters, 28(11), 837-841.

[7] Bisen, P., Baghel, R., Sanodiya, B., Thakur, G., & Prasad, G. (2010). Lentinus edodes: a macrofungus with pharmacological activities. Current Medicinal Chemistry, 17(22), 2419-2430.