Beta Glucan - Uptake Mechanism

The ileum is the section of the small intestine that extends from the jejunum portion of the small intestine to the beginning of the large intestine (colon). It is about 12 feet (3.6m) long. The jejunum is a part of the small bowel, located between the end of duodenum and the proximal part of ileum. The duodenum is the first part of the small intestine. The adult small intestine is about 20 feet (6.0m) long, and the jejunum forms a little less than half of the small intestine. The transition from jejunum to ileum is not marked by any specific anatomic structure.

Antigen uptake of Beta Glucan  occurs primarily in the ileum area through specialized cells called M cells (M = microfold). Overlying follicles that help grab key particles surround the dome shaped center of the M cells. M cells take up particulate through a mechanical process called pinocytosis (the uptake by a cell by invagination). This is a physical grabbing of the particles and pulling them through the lining of the intestinal wall. A large number of T cells, B cells, macrophages, and dendritic cells hover here and as the phagocytes engulf and digest antigen, they then present antigen markers to the T cells. It is remarkable that M cells will take soluble as well as particulate materials.

mcell beta glucan The microfold (M) cell. A scanning electron micrograph of an M cell with adjacent enterocytes. The M cell has selectively bound E. coli 0157. Note that a thick brush border is lacking, facilitating the binding and uptake of microparticles, (courtesy of Dr. Tatsuo Yamamoto, Niigata University).

M cells also have the ability to take up entire bacterial pathogens such as salmonella, viruses,
and microspheres.Macrophages and other phagocytic APCs surround these areas and is key to continuous sampling of what is grabbed by the M cells.

Also found in this area are large amounts of antibodies (immunoglobulins - IgA & IgG). These antibodies are very important to helping deactivate bacterial toxins that interfere with phagocytosis (engulfing), chemotaxis (movement of immune cells), and other very important immune response activities.

To have a clear understanding of this area of the gut associated lymphoid tissue (GALT) is to appreciate one of the major ways that our immune system is kept aware of those things that are confronting us. This also leads us to understand why we advise that immune supplements such as beta glucan and aloe MPS be taken on an empty stomach. The M cells have the ability to identify, grab, and deliver into the lining of the intestinal wall solid particles as well as living pathogens. The size of these materials may be several microns in diameter and length.

Beta Glucan is best taken on an empty stomach if you wish to facilitate the highest levels of uptake per dose. Beta Glucan is  primarily comprised on long chain polysaccharides and uptake for both would be similar. 

 

Micro anatomical features of M cells. The M cell forms a 'pocket' containing lymphocytes. The M cell actively pinocytoses soluble antigens and phagocytoses particulates such as viruses, bacteria and microspheres, (courtesy of Dr. Svein Steinsvoll, University of Oslo).