Parasitic worm secretions could treat asthma and allergies


For those with an extra-excitable immune system, a handy treatment may be round the corner – no worms required. Anthea Batsakis reports.


A scanning electron microscope image of Ancylostoma duodenale, a species of hookworm that infects humans. They ooze proteins that suppress the immune response to allergens.
David Scharf / SPL

A pill inspired by parasitic hookworms could help asthma sufferers breathe easier, according to a new study.

Led by James Cook University’s Severine Navarro in Australia, an international team gave a protein secreted by hookworms to mice and human cells in the lab, and found it stifled asthma-like reactions to allergens in both.

The work, published in Science Translational Medicine, adds to a mounting body of research looking at how parasites can be helpful in your gut rather than just a food-stealing nightmare.

Recent work from the same laboratory found hookworm proteins could treat inflammatory bowel disease. Navarro says this study builds on those results.

“We’re really excited about the potential this has and we’re really wanting to see this forward with a commercialising partner and bring this to clinical trial,” she says.

And if the treatment became clinically available, it would take on the form of a pill, she adds.

So how can swallowing a hookworm protein affect asthma?

During an allergic reaction, your body senses an invader – for instance, dust mites, a common asthma trigger – but instead seeing it as a passing tickle and moving on, the immune system overreacts.

This over-the-top response by T-cells causes inflammation. For asthmatics, it’s air passages that swell.

But hookworms living in your gut are able to escape your immune system’s wrath. They excrete anti-inflammatory protein 2, or AIP-2, which helps the parasite evade detection.

It does this by promoting tolerance, rather than kicking the immune system into high gear. In other words, it switches T-cells from being pro-inflammatory to anti-inflammatory.

Giving AIP-2 to mice, for instance, not only protects the gut from inflammation, but it also protect the airways.

Interestingly, this doesn’t mean AIP-2 will stop all immune system reactions to, for instance, a virus or bacteria, Navarro says: “It’s just allergens are being seen as ‘non-dangerous’ – if you like.”

AIP-2 proved successful with mice, and then later, on human cells taken from the pricked skin of people with a dust mite allergy.

“It seems like the protein has really re-wired and re-tuned those resident cells and can protect the host for several weeks, which in terms of mice, is a really long time,” Navarro says.

“This means it could potentially be a really long-term influence if ever given to humans.”

Navarro says their research is already ready for phase one clinical trials, where a small group of people will be tested to determine side effects and safe dosage – if funding allows.

  1. http://stm.sciencemag.org/lookup/doi/10.1126/scitranslmed.aaf8807
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