EFFECTS OF Beta-Glucan

Glucans have been known for years to have immunomodulating effects, i.e. to influence our immune system. However, we did not know how, so were referred to as non-specific immunomodulators. The only knowledge came from studies establishing their effects on macrophages.

Many years alter, in 1996, our group managed to demonstrate not only where glucan is bound, but what the general mechanism of action is. The cells of the immune system (in particular macrophages, neutrophils, some lymphocytes and natural killers) turned out to be equipped with glucan-specific receptors called CR3, to which complement fragments are also bound. And this is where it starts to be complicated and exciting at the same time.

A complement is a group of blood proteins that are engaged in numerous defensive reactions. They work reliably but cannot cope with everything. And the same applies to antibodies. In most infectious diseases, the body tries to defend itself by means of antibodies as well as the complement and all types of cells but after some time, these mechanisms become exhausted.

And the double bond of two different molecules is a trick invented by the immune system. Even at rest, CR3 receptors are present on many essential defensive cells; the individual components of the complement cascade are normally also present, but a distinctly larger amount is formed only when an infection occurs or specific antibodies exist. The very bond of the complement component called C3 (only this component binds to the CR3 receptor) to the CR3 receptors is not enough to activate the cells to full extent, and the same applies to the glucan bond as such. It means that under normal circumstances the cells are stimulated only to a lesser extent, but are ready to start as soon as they are given a real possibility.

And they have this possibility as soon as glucan as well as the C3 component of the complement are bound to the receptor. The result is turbulent - parts of the receptor change in space, with a subsequent transmission of a signal to the cell and, through a complex mechanism, its ultimate activation. The final result is a highly active cell that destroys everything foreign and improper, from bacteria to cancer cells. In addition, antibodies come to play in case of malignancy. It is clear that while antibodies in our body will not bind to normal cells, this bond will be established if cancer cells exist. But this is not enough to destroy the tumour as such because to kill the cells, it is necessary to ensure that not only antibodies and the complement, but also properly activated cells are close to the tumour. And that is where the glucan activation of the immune system becomes very handy.

It is all very similar in case of increasing blood formation damaged by radiation or chemotherapy. By means of intestinal cells, the absorbed glucans enter the bodily circulation system, are gradually released by macrophages and these released fragments bind again to CR3 receptors on bone marrow cells, which are thereby stimulated to proliferate more easily.

However, there are also other effects of glucan that we are only beginning to understand. For example, we know more about reducing the cholesterol level or preventing the unfavourable effects of stress. At present, glucans are also tested in other applications, from monitoring the blood sugar level to application in many farm animals, where they could help reduce the use of antibiotics to a large extent.

Glucans were originally tested primarily after injection and it has become obvious that there is no difference in their mode of administration - subcutaneously or intravenously. As the clinical deployment of glucans was drawing near, new studies dealing with the effects of oral glucan started cropping up. The latest comparative studies have shown that there is really no difference in the route of administration. The mechanism of passage of glucan through the intestine is roughly as follows: glucan activates the macrophages of the Peyer's patches, which then migrate to other organs, where glucan and its fragments are released slowly. Glucan is therefore distributed throughout the body, where it once again binds to its receptors and activates cells.