Immune system block alleviates asthma
7 November 2007
Blocking a signalling molecule that helps to control the immune system could be an effective way to treat asthma. IL-25 is one of a family of molecules known as cytokines that are released by white blood cells and are crucial in controlling immune reactions.
Research led by Dr Andrew McKenzie of the MRC Laboratory of Molecular Biology has shown that if the cytokine IL-25 is blocked the symptoms of allergic asthma in a mouse model of the condition are alleviated.
The study is reported in the Journal of Allergy and Clinical Immunology.
The number of asthma sufferers has increased dramatically over recent decades; the World Health Organisation estimates that up to 300 million people worldwide suffer from the disorder. The charity Asthma UK reports that 5.2m people in the UK, including 1.1m children, currently receive treatment for asthma.
Allergic asthma is the result of a breakdown in the normal function of the immune system. Normally harmless stimuli, for example pollen and dust, lead to uncontrolled immune responses. This can cause the muscles in airway walls to contract which leads to wheezing and shortness of breath. The difficulty in breathing that follows is made worse by inflammation of the airway lining and build-up of mucus that further constricts the airways.
Dr McKenzie and his team have developed a novel monoclonal antibody (an antibody designed in the lab to bind to one target) that stops the immune reaction.
In experiments using a mouse model of allergic asthma, treatment of the mice using the anti-IL-25 monoclonal antibody prevented the narrowing of the airways, wheezing and lung problems associated with allergic asthma.
Dr Mckenzie said:
In a mouse model of asthma, the antibody completely prevented airway hyper-reactivity even when given late in the response and suppresses airway inflammation, if administered early. Our results highlight a new molecular target in asthma.
Of course it is important not to overplay the importance of this finding given that we don't know if it will work in the same way in humans. However our results indicate that IL-25 could be a central mediator in the asthma response and that we have an inhibitor that works very effectively in experimental models, he continued.
The monoclonal antibody used in the mouse model experiments also blocks the interaction between human IL-25 and its receptor. In response to this, scientists working for MRC Technology are developing a version of the monoclonal antibody that is safe for use in humans, a process known as humanisation.
Original research paper: Blocking IL-25 prevents airway hyperresponsiveness in allergic asthma is published in the Journal of Clinical Immunology.
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