A University of Dundee researcher has uncovered why parasitic worm infections seem to protect people from developing asthma, paving the way for potential future treatments for the disease.
Although it has been known for some time that parasites called roundworms, which live in the intestines of people and animals, can prevent the development of allergic immune responses, scientists have been unable to explain how this happens.
Dr Henry McSorley, from the Division of Cell Signalling and Immunology in the School, led research examining how worms interfere with the parts of immune system which cause allergy. He and his colleagues discovered that worms secrete a molecule called HpBARI that blocks key signals between cells of the immune system associated with allergic responses.
The presence of HpBARI alone was enough to prevent the development of asthma in mouse models, while the researchers also found that it blocked the same pathway in human cells.
“Parasitic worms are complex creatures that evolved to survive inside our body,” explained Dr McSorley. “One of the ways they did this was by developing sophisticated techniques to avoid elimination by our immune system.
“They release molecules which block immune responses that would otherwise kill them. Importantly, the same immune responses that kill parasitic worms are also responsible for causing allergies and asthma.
“Populations with high rates of worm infections tend to have less asthma. In the developed world over the last century we have been very successful at getting rid of worms but have seen a huge rise in allergic diseases at the same time. Therefore, we believe that parasite secretions could contain new treatments for allergic diseases.”
Asthma causes inflammation in the airways and ranges in its severity from mild to life-threatening. Pets, pollen and house dust mites are among the common triggers for asthma attacks so treatments that inhibit allergic responses have the potential to significantly improve the lives of patients.
A particularly important aspect of the allergic immune response is a messenger molecule called IL-33, which is released in the lung when an allergen is inhaled and its release is one of the critical steps in the development of asthma in susceptible people.
HpBARI binds to and blocks the receptor for IL-33, preventing IL-33 from transmitting its signal. Due to this activity, Dr McSorley’s team found that HpBARI was very effective in preventing the development of allergic immune responses and believe that it could potentially be used to prevent asthma.
“In order to develop this towards new medicines, further work needs to be carried out to determine exactly how HpBARI is so effective at blocking the IL-33 receptor,” continued Dr McSorley. “From there we will examine whether this could be safely developed towards new medicines for administration to people living with asthma.”
The research is published today in the journal eLife.
Image: wormuvian (credit Hana Pokojna). Wormuvian depicts the worm as Da Vinci’s Vitruvian man, with the two immunomodulators discovered by the McSorely lab (HpARI and HpBARI) represented as either set of hands.