The gastrointestinal tract and the immune system works closely together to keep the body balanced and to keep potentially dangerous organisms from upsetting the carefully mapped out DNA functions put in place at the beginning of life.
Overall, the immune system polices the whole body and its function is toward health and wellbeing; the function of the intestinal system is to keep the body supplied with fuel and nutrients—proteins, fats, carbohydrates—that are necessary for the body to function. Contained in this list of functions of the intestinal tract is the need to supply nutrients to the immune system and to keep it healthy. If not that, at least to keep it functioning at whatever level it’s capable of performing.
The gastrointestinal tract opens to the outside world and this long passageway is well equipped with immune cells to deal with potential invaders from without. It and the respiratory system must deal with intrusions that threaten to sabotage the normal functioning of the body; they employ the aid of the immune system to control or to eliminate offending organisms. Thus the immune system is an important working part of the intestinal tract. In some sense it’s a two way system where one system enhances the other. Where one is lacking the other supplies, and when one is in distress the other intercepts the call and rushes forward aiding whenever possible.
Immune cells inhabiting the intestines
Cells relating to immune functions are embedded in the lymphoid tissue of the intestines. While the immune system has lymph nodes scattered throughout the body as well as way stations to collect discarded materials from the aftereffects of successful immune system putdowns, the intestines have Peyer’s patches, lamina propria lymphocytes and intraepithelial lymphocytes.
Peyer’s patches are little nodes, layered patches resembling in function lymph nodes, that typically appear in the distal ileum—the third and last part of the intestines—but appear in the jejunum—the second part of the intestines—in a small portion of the population. These are small follicle like projections closely packed together whose function is much like that of regular lymph nodes of the immune system.
In addition to these well understood combined functions of the intestines and the immune system, other specialized cells are being discovered that aid in this important disease resisting function of the two systems. Studies and testing are ongoing going and have been made more valuable since the DNA mapping project has been completed.
“To mediate immunity over such a large and active area, there are more lymphocytes associated with the intestine than there are in the entire rest of the human body.”
The preceding are the words of one researcher who delves into the ways the intestines and the immune response work. Daniel Mucida, Ph.D. an assistant professor at the Laboratory of Mucosal Immunology at The Rockefeller University has as his aim to learn all there is to know about the connection between the intestinal track and the immune system.
This work is important because there’s an enormous amount to learn about the various disorders afflicting the alimentary canal that’s either glossed over as irritable bowel syndrome—a medical diagnosis meaning ‘we don’t really know’.