University of Manchester scientists have discovered why some people are naturally protected against parasitic worms living in the guts of a billion people worldwide.  

Whipworm

Parasitic worms, like the hookworm, and the spiral threadworm, are a major threat to humans worldwide, but they also affect other animals, including our pets and livestock.   

“These parasitic worms live in the gut, which is protected by a thick layer of mucus.  The mucus barrier is not just slime, but a complex mixture of salts, water and large ‘sugar-coated’ proteins called mucins that give mucus its gel–like properties,” says Dr David Thornton, from the University’s Wellcome Trust Centre for Cell Matrix Research.

Experimenting on mice with worms (whipworm Trichuris muris),  that are similar to those living off humans ( Trichuris trichiura), scientists made the breakthrough by discovering that mice without Muc5ac in the mucus in their intestines couldn’t get rid of the worms.  

 “We previously found that mice that were able to expel this whipworm from the gut made more mucus. Importantly, the mucus from these mice contained the mucin, Muc5ac. This mucin is rarely present in the gut, but when it is, it alters the physical properties of the mucus gel,” Dr. Thornton said.

Professor Richard Grencis, from the Faculty of Life Sciences, and Co-leading the project, said:  “For this new research, we asked how important Muc5ac is during worm infection by using mice lacking the gene for Muc5ac. We found that mice genetically incapable of producing Muc5ac were unable to expel the worms.”   

The infected mice, despite having a strong immune response against the worms suffered long-term infections.   The importance of Muc5ac found in the guts of mice able to reject worms of is that “it is ‘toxic’ for the worms and damages their health,” Professor Grencis said. 

The University of Manchester discovery of Muc5ac's  importantance in the expelling of parasitic worms, was reiterated by Dr Sumaira Hasnain, the lead experimentalist on the project who said:  “For the first time, we have discovered that a single component of the mucus barrier, the Muc5ac mucin, is essential for worm expulsion. Our research may help to identify who is and who isn’t susceptible to parasitic worms and it may eventually lead to new treatments for people with chronic worm infections.”

The study, published in the Journal of Experimental Medicine and featured in Nature’s ‘research highlights’