McMaster University

McMaster University

Faculty of
Health Sciences

Researchers to study the immune system in cat allergy sufferers

Published: June 7, 2012
Mark Larché
Mark Larché, principal investigator of the study, professor of medicine of the Michael G. DeGroote School of Medicine and Canada Research Chair in Allergy and Immune Tolerance

A year ago, pet lovers around the world applauded McMaster University researchers for their development of a vaccine to treat people with an allergy to cats.

The questions that remained were exactly how this vaccine works and how it changes the immune response to protect patients.

That puzzle is expected to be solved as researchers undertake a five-year study of the vaccine supported by a $6.4 million grant to McMaster University from the National Institute of Allergy and Infectious Diseases, part of the U.S. National Institutes of Health. The study will also investigate precisely how the white blood cells that are targeted by the vaccine contribute to asthma.

Millions of people around the world are allergic to cats. While it’s commonly believed cat hair is the cause, the true allergen is a protein found in the dander and saliva of cats which the allergy sufferer breathes in. Sensitivity to cats is responsible for almost 30 per cent of allergy-related asthma.

For their study, the researchers based at the Firestone Institute for Respiratory Health at St. Joseph’s Healthcare Hamilton will recruit patients with cat allergies including those with asthma.

Depending upon the severity of their disease, participants will take part in different clinical studies including a clinical trial of the peptide vaccine. Their progress will be followed over several months.

"We will study how the immune system drives these diseases and how the vaccine returns the immune response in allergic subjects to 'normal'," said Mark Larché, principal investigator of the study, professor of medicine of the Michael G. DeGroote School of Medicine and Canada Research Chair in Allergy and Immune Tolerance.

He asked that allergic individuals who would like to take part in this research should contact the team at cat-allergy@mcmaster.ca.

Through its collaborating centre at the Benaroya Research Institute in Seattle, the team have access to new tools that will allow them to identify the very rare white blood cells that are triggered by the offending cat protein. The Hamilton researchers, who have established the NIH Allergen Epitope Research and Validation Centre, will use these tools to identify the cells in the blood of asthmatic subjects and allergic subjects being treated with the vaccine.

The vaccine was developed by deconstructing the cat allergen molecule and identifying short chains of amino acids (peptides) that can alter the function of the rare white blood cells that drive the disease.

A low dose of the vaccine is given into the skin. Patients do not experience the side effects of traditional allergy shots.

The clinical development of the vaccine is being undertaken by Adiga Life Sciences, a joint business venture between McMaster and Circassia Ltd., a UK-based biotech company.

In 2011, Larché presented results of a clinical trial of the cat allergy vaccine, led by Circassia and Adiga, showing that patients who received four doses of the vaccine maintained a statistically significant reduction in symptoms one year later.

"The NIH study will also follow patients for one year but will look at mechanisms of action of the vaccine, rather than the efficacy of the vaccine," Larché said.


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