Science and Technology for Canadians

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Summary

Dr. Hari Vijay, a research scientist at Health Canada has developed internationally recognized research on the standardization of mold allergens. About 20% of Canadians suffer from allergic reactions to molds, major contributors to respiratory allergic symptoms and asthma. The current treatment of choice for these conditions is hyposensitization with allergen extracts.

Currently available commercial extracts are not standardized and relatively crude. Consequently, their use carries a high risk of anaphylaxis (fatal allergic reactions to the extracts). In 1975, Dr. Vijay initiated a program for the standardization of mold allergens. Since that time her team has been conducting cutting-edge research in the field. Dr. Vijay has been able to develop a total of fourteen physico-chemical and immunological techniques to purify and characterize mold allergens. Her work (when it becomes available at the bedside in a few years) will come as a relief to many sufferers of symptoms from the cruder extracts.

Transcript of Video

Gillian Deacon
Anyone who suffers from allergies knows how debilitating they can be. Tonight on Earth Tones, how some Canadian research could make life a lot easier for millions of people around the world.

Dr. Hari Vijay
We have been working for the past 26 years on this research work. Now we are on the verge of this exciting moment to produce a safe vaccine for desensitization of mold-allergic patients.

Gillian Deacon
When Dr. Hari Vijay began studying molds in 1974, little was known about which compounds in the spores caused allergic reactions. Patients receiving allergy shots were given crude mold extracts. There were no standards for vaccines, so their potency and composition varied. This lead to adverse reactions in some patients, and even anaphylactic shock, a severe allergic reaction that can be life threatening. Dr. Vijay's goal was to standardize mold extracts and to come up with a safe vaccine - one free of toxins and irritants - that would protect against allergy symptoms without causing them.

Dr. Vijay focused her efforts on two molds commonly found indoors: alternaria and cladosporium. She set about isolating the major allergens in the molds, the compounds that cause reactions in about 90 percent of the people allergic to them. Along the way, she developed 14 techniques for purifying and identifying mold allergens.

Dr. Hari Vijay
When we purified the major allergen by traditional techniques we didn't get an adequate amount of the purified allergen and therefore it could not be distributed widely, therefore we thought our best way is to take the challenge and do the gene cloning. We did the cloning and we cloned major allergens from alternaria and from cladosporium as well.

Gillian Deacon
With the cloning of the molds' major allergens in 1995, Dr. Vijay was one step closer to her dream of a safe vaccine.

Dr. Hari Vijay
The large part of the population were allergic to pure... who are allergic to major allergen, you can inject that major allergen which has no other proteins lingering around, and the patient is very safe. He's getting just the protein to which he's allergic to. So he can be effectively desensitized.

Gillian Deacon
Human trials of Dr. Vijay's extracts are underway, but she's already working on refining her mold vaccine even further. The major allergen is actually a long string of proteins. Dr. Vijay is in the process of determining which proteins, called peptides, in the string will induce a protective response without producing allergy symptoms. She expects to have her peptide vaccine ready in two to three years. At the cutting edge of allergy treatment, peptide vaccines have been developed for among other things, cat and pollen allergies. Once she's developed a safe and effective peptide vaccine for mold allergies, Dr. Vijay would like to analyze other types of allergens.

Dr. Hari Vijay
I would like to do, not with molds only, but with thousands of allergens which are waiting to be analyzed... thousands and thousands of allergens. So much work is to be done. It has absolutely great implications!

Gillian Deacon
Dr. Vijay's groundbreaking work in developing safe and effective vaccines has great implications, not just for Canadians, but for allergy sufferers around the world.

Earth Tones is produced in co-operation with Health Canada.