05 April 2012

Asthma Vaccine

Bronchial asthma is a chronic inflammatory disease of the respiratory tract, the cause of which in most cases is abnormal sensitivity to environmental allergens. Such hypersensitivity leads to the development of an inflammatory process in the bronchi and bronchioles that disrupts the patient's breathing process. Around 300 million people suffer from asthma worldwide, while the number of patients with this disease has doubled over the past 10 years. Every year, almost 250,000 people die prematurely due to asthmatic respiratory disorders.

Most often, asthmatics are prescribed medications that have a symptomatic effect, which bring temporary relief, but do not cure the disease. An alternative is a long–term protocol of desensitization - specific immunotherapy, which consists in the introduction of gradually increasing doses of allergen in order to reduce hypersensitivity and the severity of symptoms with subsequent exposure. However, the effectiveness of such therapy is limited and varies greatly from patient to patient.

Of the approaches currently being developed to combat allergic asthma, vaccination looks the most promising. French researchers from the INSERM Institute and the University of Nantes, working under the leadership of Bruno Pitard, have developed an innovative nanovector DNA vaccine, the action of which is directed against one of the most common allergens that cause a reaction in patients with asthma, the Derf1 protein. This protein is part of the body of dust mites (Dermatophagoides farinae).

The active component of the vaccine is a DNA fragment encased in a plasmid encoding the Derf1 sequence attached to a nanosphere made of a synthetic polymer. When such a vaccine is administered intramuscularly to mice with simulated asthma, Derf1 protein production starts in the animal body. This, in turn, directionally stimulates the immune system, which is manifested by launching a specific cellular immune reaction against this allergen, as well as the synthesis of antibodies directed against it.

The result of double administration of the vaccine with an interval of 3 weeks was suppression of hypersensitivity to the allergen and, accordingly, a decrease in the severity of the inflammatory reaction associated with the disease. At the same time, lower levels of inflammatory cytokines were recorded in the lung tissue of vaccinated animals with asthma than in the lung tissue of unvaccinated animals of the control group.

Currently, the experimental nanovector DNA vaccine is at the stage of regulatory preclinical development, after which the researchers hope to move on to clinical trials.

Article by Fanny BEILVERT et al. DNA/amphiphilic block copolymer nanospheres reduce asthmatic response in a mouse model of allergic asthma published in the journal Human Gene Therapy.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on INSERM: Asthma: a vaccination that works using intramuscular injection.


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