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When the wind gusts from the northwest on a sunny October day, a quaint ritual occurs across the southern states of Australia. For every person enjoying the spring sunshine, there is another found weeping into a hand- kerchief, eyes ablaze and nose gushing like a fountain. It's hayfever time. By David Bruce Melbourne has acquired a reputation as the allergy capital of the world. The reason is simple. Across the north and west of the state of Victoria are large tracts of farming land with hectares of rye grass. When the weather is 'just right' -- any time between early spring and late summer -- the rye grass paddocks produce pollen at the rate of around half a tonne per hectare. When the winds blow from the northwest, they pick up the pollen grains and carry them directly to the populated regions of southern Australia. While many people are unaffected, others respond to the invading grass pollen grains, which force their bodies to react in a variety of ways, most commonly with what we recognise as hayfever and/or allergic asthma. Perhaps not surprisingly, one of the world's leading allergy research teams is located in Melbourne, in Monash University's Department of Allergy, Asthma and Clinical Immunology at the Alfred Hospital. "We want to understand these grass pollen allergens at the molecular level in order to pave the way for the design of safer and more effective therapeutic reagents." Dr Cenk Suphioglu, a senior research fellow internationally known in his field of grass pollen allergy, is working on a series of research projects with the department's leading allergy scientist, Professor Robyn O'Hehir, in a quest to understand why these pollen allergens cause so much grief to humans. "We want to understand these grass pollen allergens at the molecular level in order to pave the way for the design of safer and more effective therapeutic reagents," said Dr Suphioglu. "Grass pollen grains need to be released into the air for fertilisation and seed set, but, as an unintended consequence, they can affect humans."
However, as a result of the cascade of events which follow, specialised human cells are ruptured in the battle, releasing histamines that give rise to the symptoms of hayfever. On the other hand, allergic asthma is triggered by grass pollens which, after rainfall, burst, releasing hundreds of allergenic micronic particles that gain access to the lower airways. This mechanism of grass pollen-triggered asthma was discovered by Dr Suphioglu in 1992. The current methods of allergy treatment are not always effective, and in some cases can produce annoying side-effects or local reactions, according to Dr Suphioglu. Sufferers either take nose sprays or oral drugs (anti-histamines) for short-term relief, or they undergo long-term immunotherapy, a heavy-handed approach which blocks the immune response to a range of allergens. "We need reagents that are more effective and safer than the existing methods," Dr Suphioglu explained. "As a result of our ongoing molecular studies (funded by the NHMRC, Autogen Limited and the Cooperative Research Centre for Asthma), we are currently working to identify synthetic molecules that block the interaction between the allergen and the antibodies, since it is this interaction that results in the allergic response." By using gene isolation and sequencing technology, the Monash team has isolated the DNA of the rye grass pollen allergens and identified areas of such allergens that interact with the antibodies. "With such novel information, we can now create modified allergens that can no longer interact with the antibodies and therefore be safely used in immuno-therapy to switch the immune response from allergic to non-allergic," said Dr Suphioglu. Another approach currently used by the Monash team is to isolate the DNA of the human antibodies themselves, in an attempt to identify and design synthetic molecules that block allergen-antibody interactions and therefore prevent allergic reactions. Targets interactions While the approach employing modified allergens in immunotherapy makes the immune system tolerant towards the exposed allergens, the latter approach specifically targets the allergen-antibody interactions. "With the two procedures at hand, we are now at a very exciting stage of allergy research which promises to pave new and exciting ways for novel allergy treatment strategies in the near future," Dr Suphioglu concluded.
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