Not every yeast cell wall product has the ability to influence the immune system. The major challenge is to remove the other components of the yeast cell wall, such as manno-proteins and lipids (attached to the end points of the side branches in the intact cell wall) without damaging the beta-1,3/1,6-glucan molecule. It is clear that not all glucans can enhance the immune system (like cellulose and starch). The specific structure (length of the chains and branching frequency) of beta-1,3/1,6-glucans determines if the molecule can be recognised by the immune cells and stimulate a response.
How can beta-1,3/1,6-glucans be recognised?
White blood cells (e.g. macrophages, dendritic cells) are immune cells in the front-line of the defences of the body. The white blood cells have receptors on their surface, these receptors can recognise invading pathogens (e.g. bacteria, viruses, fungi, parasites) but also beta-1,3/1,6-glucans. A highly specific ‘key-in-lock’ type of interaction between the beta-1,3/1,6-glucan and the receptors on the cell surface triggers the immune cell to release anti-microbial substances and alarm signals (or cytokines) into the bloodstream. To match perfectly into the receptors of white blood cells the specific structure of the beta-1,3/1,6-glucan (length of the chain and branching frequency) is for this reason, very important.
The majority of the immune cells (approximately 75%) are found in the body surfaces, particularly in gut endothelia, the largest immunological organ in the body. The activated immune cells in the gut endothelia release the alarm signals or cytokines into the bloodstream. This will not only stimulate the a-specific immune system but also the immune status of the whole body (specific immune response) will be activated by orally ingested beta-1,3/1,6-glucans. This leads to an enhanced phagocytosis by macrophages, activation of the production of specific immunoglobulins and the counteraction of harmful side effects of the immune system. Activation of immune cells in the gut by beta-1,3/1,6-glucans do not only have a positive influence on gut health, scientific evidence supports that it can also reduce immune disorders in the rest of the body.
Does an activated immune cell always provide the same immune responses? No, immune cells are equipped with several surface receptors that discriminate between different substances. Beta- 1,3/1,6-glucans stimulate anti-microbial activity, cellular defence and an anti-inflammatory response. Bacteria and other pathogens bind to other receptors on the same immune cells and stimulate other immune responses; bacterial lipopolysaccharides (LPS) for example interact with another receptor on the macrophages which induce inflammation and fever.
MacroGard, the most researched betaglucan
The product MacroGard (produced by Biorigin and distributed in major European markets by Orffa Additives) is the most well known beta- 1,3/1,6-glucan product for animal nutrition. There is a large scientific dossier available that shows the beneficial effects of MacroGard. Both in vitro trials and in vivo research with several animal species has shown the beneficial effects on immune parameters and animal health.
In vitro trials show that the source and type of beta-glucan is extremely important for efficacy. Several Universities worldwide, including the University of Ghent, carried out extensive in vitro research where different sources and types of betaglucans were evaluated for their capacity to modulate several different immune cells. Research showed the high efficacy of MacroGard on immune cells.
In vivo research by several universities and research institutes show that MacroGard has beneficial effects on the health status of animals during pathogenic pressure as well as during (chronic) inflammatory situations. For example, in pet animals it is shown that dietary MacroGard reduces the clinical signs of arthritic disorders and atopic dermatitis. It supports the natural defences and protection in young puppies. Latest research has shown beneficial effects of MacroGard on the metabolism and appetite control in obese dogs with insulin resistance.
Beta-1,3/1,6-glucans have several beneficial properties and many useful applications. Beta-1,3/1,6-glucans, found in the cell wall of yeast, are known for their ability to optimise immune response. In vitro work shows that it is very important to have the correct type and structure of beta-1,3/1,6-glucan. Commonly used yeasts, yeast cultures or complete yeast cell wall products do not have this particular ability to stimulate immune response. MacroGard is the most researched beta-1,3/1,6-glucan. The product has been investigated intensively and has proven to be very efficient in both in vitro trials and animal trials in pets, horses, livestock and aquatic species.