Uptake Mechanism of
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.
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,
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
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).