Development of Human Nasal Challenge Models With Microbial Constituents and Grass Pollen: Monophosphoryl lipidA, Poly-inosine-cytosine, Poly-inosine-cytosine Stabilised With Poly-L-lysine and Carboxymethylcellulose, Resiquimod, Tuberculin and Timothy Grass Pollen

The investigators propose the development of a range of nasal spray challenge models to study the way the nose can respond to different types of nasal challenge that elicit different forms of inflammation.

The investigators will carry out nasal challenge with bacterial and viral components and allergens. In this way the nasal upper respiratory tract mucosa is challenged with stimuli of the immune system, causing various types of inflammation. Samples will be taken by blotting the nostril surface and by scraping off tiny surface samples.

The nose will be sprayed with a substance that is a single part of a bacteria or virus, or with an allergen. The material delivered by nasal spray is of high purity and is sterile, containing no live bacteria or viruses. The nasal spray substance contains molecular patterns that are recognised as foreign by the immune system, and at the right dose should stimulate the immune system, causing mild nasal inflammation. The study employs noninvasive methods of sampling using absorptive strips. These strips look and feel like tissue paper, and are applied to each nostril for a period of 1 min. A few pinhead-sized tissue samples are taken from inside the nose, using a small disposable sterile plastic probe that has a tiny scoop on its end. In the nasal lining fluid and tissue samples, measurement will taken of a range of molecules and cells that protect against infections and help the immune response.

By spraying the nose with a challenge agent in this manner, the nasal immune response can be assessed, which can help us better understand how the human immune system cells and molecules respond to bacteria and viruses. In the future, this may allow the testing of new drugs and vaccines, by seeing if they decrease or stop the inflammation after the nasal challenge.