Rights: The University of Waikato Published 18 October 2010 Download

Professor Graham Le Gros from the Malaghan Institute explains how the hookworm suppresses our immune system in order to remain in the body. He realises that this could work to our advantage: there are many diseases where the immune system is overactive, such as asthma, and enzymes from hookworm could be used to calm the immune system in these instances.


Let me tell you some of the things that the hookworm does to escape the immune system, because it’s a pathogen. It’s not one of those ones that neutrophils can deal with. It’s got enzymes that it secretes when it’s trying to burrow through the skin, which actually just dissolves the skin, and it just burrows in.

It’s just the right size that it fits in all our blood vessels and doesn’t actually hurt us when it goes through the bloodstream by the way. It just wriggles in its very special way, and it’s very small. It is about a millimetre long – you all know a millimetre on your ruler – that is how big it is, and then it just hits the blood vessels in your lung, and then it just gets a little bit bigger and just bursts through there and just absorbs some of the nutrients, and then it gets up the throat, gets swallowed and then lives in the gut.

When it’s there, it secretes lots of enzymes because it wants to sit there quiet and just feed off us. But our immune system is trying to attack it. So it’s designed for itself a lot of hormones and enzymes that suppress our immune system – cloaks itself with our body’s own proteins as well – and so it sits in the gut secreting these enzymes that just suppresses the immune system and keeps the gut all sort of happy so we don’t even know it’s there.

I’ve described how the hookworm is bad, but there could be some good use to the hookworm too. This is a pathogen that actually can suppress our immune system, and we have many diseases where our immune system is overactive, and we are looking at the way the hookworm can be exploited or used to good.

We don’t work with the human hookworm here – it’s not necessary. We actually have a mouse or rat version of the hookworm, and it does the same job the same way, and it’s in all the mice and rats of New Zealand, it’s just a natural thing. But we can actually pull out the enzymes that that worm makes – very comparable to what the human hookworm makes – and start to test it to see which is the right one, and we can take the right bit from it which actually suppresses the immune system in a bad disease setting.

We try and grow them and culture and dissect apart which of the things which suppress the immune system. And we find the hormone, ah, and we will try and clone that. And then we would try and package that into a medicine or therapy that could be used to treat say asthma because they can actually calm down that inflammation when it’s inappropriate and against something which is not a parasite.

CDC Centres for Disease Control & Prevention