Although parasitic nematodes (sometimes called worms) infect up to a billion people worldwide, a few people seem to be naturally immune to the little invaders. Researchers from the University of Manchester, the University of Texas and the NIH may have discovered the secret of their success. They make the right kind of intestinal mucus.
We all have a thick layer of mucus in our guts. Among its other components are proteins called ‘mucins’. It’s these sugar-coated mucins that are responsible for the gel-like properties of mucus. Upon closer examination, the scientists found that mice that were able to rid themselves of parasitic nematodes (specifically the whipworm Trichuris muris) contained the mucin Muc5ac. The hapless mice that did not have this particular mucin could not expel the nematodes.
The mouse whipworm Trichuris muris.
Credit: R. Grencis
Very similar types of intestinal nematodes infect humans, some of whom also make the Muc5ac mucin. Those people can efficiently eliminate not only whipworms, but other types of nematodes as well (hook worms and spiral threadworms).
Mice that make Muc5ac are a small minority. It’s not yet clear what percentage of the human population makes this mucin and thus is largely immune to nematode infection. However, this new data could help doctors determine which individuals are susceptible to parasitic worms and potentially create treatments for those that are.