Cobwebs in Your Gut: Possible Cure for Crohn's Disease? Our bodies use a variety of different parts to make up its immune system and just when you thought scientists knew every one of the different parts and how they worked, they discovered something new.

Inside your intestines are a group of molecules known as human alpha-defensin 6 or HD6 cells. Although researchers knew they played a role in the immune system, they were never sure of exactly how the molecules functioned in that role.

Researchers Charles L Bevins, professor of microbiology and immunology at the University of California as Davis, Andreas BÓ“umler, professor and expert in bacterial pathogens also from UC Davis, Robert I Lehrer, professor emeritus from UCLA, and Wuyuan Lu, professor of chemistry at the University of Maryland School of Medicine have recently collaborated on a study of HD6. The nine year study was actually spearheaded Hiutung Chu, who started out as a graduate student under Bevins, but now has achieved the position of fellow at the California Institute of Technology.

What they did know is that defensins in general are found in plants and animals worldwide and they generally play roles in defense and immune mechanisms. In humans, there are six different defensins produced. Among those are HD5 and HD6, which are both produced by Paneth cells located in the folds of the interior lining of the small intestines. Paneth cells are secretory cells that produce a secretion that along with the intestinal stem cells help maintain a balance in the micro fauna of the intestinal tract.

HD5 has been well studied and scientists have recognized its antibacterial properties. However, little has been known about the role of HD6. One thing they did know is that HD6 did not kill bacteria like HD5 did. In conducting their research, Chu discovered that whenever HD6 was added to a suspension of bacteria or fungi that a white film-like substance formed. In his research, BÓ“umler discovered that even though HD6 did not kill Salmonella bacteria, it did protect the organism, in this case a transgenic mouse, from what should have been a lethal infection. When the two collaborated on their findings, they began to realize that HD6 works in a unique way to prevent bacterial infection without killing the harmful bacteria.

Further studies with Lehrer and Lu revealed that the white filmy substance Chu had observed was actually a microscope cobweb of fibers that trapped the harmful bacteria, much like a spider’s web catching and holding insects. Once trapped by the HD6 cobwebs, other immune factors such as HD5 and white blood cells can then come in a attack the trapped harmful bacteria.

The news of this discovery is being hailed in the medical community as possible opening a pathway to develop a way to control or even cure Crohn’s disease. Crohn’s disease is a chronic inflammation of the bowel and has been associated with deficiencies in HD5 and HD6. Knowing how they both operate should help other researchers in the fight against this crippling disease.

HD6 and the cobweb like net it forms to ensnare harmful bacteria such as Salmonella is another shining example of the complexity of the human body and how wonderfully designed we are, even down to the molecular level. As I was reading the report on HD6 and how it works, I couldn’t help but relate it to how a spider in the shrubs outside our house spun and intricate web which then trapped a lacewing. The spider rushed in and covered the insect with more webbing so that it couldn’t escape.

Like so many times before, I pose the question as to how all of this, the Paneth cells, the HD5 and HD6 all evolved at the same time so as to carry out their mission to help protect us from harmful pathogens? As a trained biologist, I don’t see how it possibly happened by random chance. The parts are too well designed to work together for the good of the entire body. I know that the HD in HD6 stands for human alpha-defensin, but I kind of like to think of it as standing for His Design.


Immune System Molecule Weaves Cobweb-Like Nanonets to Snag Salmonella, Other Intestinal Microbes, Science Daily, June 21, 2012.