The humble tick isn't often viewed as an ally of human health (see page 524), but one British biotechnology company is banking on its hidden charms.

Reading-based Evolutec holds patent rights on a number of proteins found in the saliva of ticks, and some are already showing clinical promise, particularly for the treatment of allergies and inflammation.

The proteins' potency derives from a tick's need to evade detection while it feeds on its animal host. Its saliva contains a number of molecules that suppress its victim's immune response, allowing the tick to feed for days unnoticed.

On target: protein rEV131 binds to histamine at two sites (yellow). Credit: EVOLUTEC

“It's the tick's stealth technology,” says Mark Carnegie Brown, Evolutec's chief executive, adding that it's a technology that is yielding molecules with therapeutic potential.

The story began almost 20 years ago at a laboratory in Oxford run by the Natural Environment Research Council (NERC), when researchers led by virologist Patricia Nuttall started investigating how ticks use proteins in their saliva to suppress the immune system of their hosts.

Nuttall, who now directs the NERC's Centre for Ecology and Hydrology in Swindon, soon discovered an array of proteins of interest. “These molecules have been refined by millions of years of evolution,” she explains. “There are no toxicity problems, they work on a range of animals, they aren't fragile — and there are an awful lot of them.”

One of the most promising proteins, dubbed rEV131, binds to histamine, which, when produced by the body in excessive amounts, is associated with allergies and inflammation. Anti-inflammatory drugs tend to work by blocking one of at least four different histamine receptors in the body, but Nuttall describes rEV131's behaviour as “much more efficient”. The tick protein grabs hold of the histamine itself and so stops it binding to the receptors.

The commercial potential seemed clear, and in 1998 Evolutec emerged as the first spin-off company from the NERC, backed by 3i, the London-based venture-capital group. The patents were held by the NERC, rather than the scientists, and the company was set up separately from the research team — although Nuttall served as a non-executive director from 2000 to 2003, and is still advising the company on the possibility of using the proteins to vaccinate animals against ticks.

Last year, rEV131 was shown to be effective for treating hay fever in a second-stage clinical trial run by Paul Ratner, an allergist who runs Sylvana Research in San Antonio, Texas. Evolutec plans to run a second phase II trial this year to determine the right dose and frequency for the therapy. This stage will be critical to the company's prospects for making it big, says Michael Aitkenhead, an analyst at Bridgewell Securities in London. Last September, Bridgewell organized Evolutec's second round of financing in 2005; between them, the two rounds raised nearly £20 million (US$36 million) from institutional investors.

Evolutec, which was first listed on London's Alternative Investment Market in August 2004, has a small core of just 11 full-time staff. It subcontracts out many operations including the running of clinical trials, and has enough cash to keep going for another 18 months as it searches for a partner to take rEV131 through the large, phase III trials needed for regulatory approval.

The tick protein is also in trials for suppressing inflammation after cataract surgery and for treating ‘dry eye’. But it is only one of 16 proteins from tick saliva that Evolutec holds patents on or applied to patent; some show promise in animals for treating heart attacks and autoimmune diseases. The firm also has a partnership with animal-health company Merial of Duluth, Georgia, to use one of the proteins as a vaccine against both ticks and tick-borne diseases in cattle.

Carnegie Brown says he jumped at the chance to join the young company in 2003 “for the opportunity to build a business with some really fascinating technology”. The company has enough funds to do at least three clinical trials in 2006, he says: “There's a whole series of strings to our bow.”