Researchers have tested a newly developed vaccine that could confer long-term protection against allergic asthma, reducing the severity of its symptoms.
Their research in animals has been published in the journal Nature Communications.
Asthma affects 340 million worldwide. It is a chronic disease of the air passages characterised by inflammation and narrowing of the airways in response to allergens such as dust mites. Symptoms of asthma include shortness of breath, cough, and wheezing.
Exposure to dust mites and other allergens leads to the production of antibodies called immunoglobulin E (IgE) and type 2 cytokines (such as interleukin-4 (IL-4) and IL-13) in the airways. This leads to a cascade of reactions resulting in hyperresponsiveness of the respiratory tract, excessive mucus production, and eosinophilia (when there are too many eosinophils, a type of white blood cell, in the airways).
Currently, inhaled corticosteroids are the gold standard for controlling asthma — but in the case of severe asthma, this treatment is not enough. Then, it is necessary to use therapeutic monoclonal antibodies that target IgE or the IL-4 and IL-13 pathways. These are costly treatments, however, requiring long-term or even lifelong administration of injections.
To solve this, the researchers developed a conjugate vaccine, called a kinoid, by coupling the recombinant cytokines IL-4 and IL-13 with a carrier protein called CRM197 (a non-pathogenic mutated form of the diphtheria toxin, used in many conjugate vaccines).
The preclinical results from animal models demonstrate that this vaccine induces the sustained production of antibodies specifically directed against IL-4 and IL-13. The vaccine was so effective that six weeks after the first injection of the conjugate vaccine, 90% of the mice presented high levels of antibodies. Over one year after primary immunisation, 60% of them still had antibodies capable of neutralising IL-4 and IL-13 activity.
The vaccine was also shown to strongly reduce levels of IgE, eosinophilia, mucus production and airway hyperresponsiveness in a model of dust mite allergic asthma. This study therefore suggests both the prophylactic and therapeutic efficacy of the vaccine in this model of asthma and no adverse effects were observed in the animals. The next step for the researchers will be to test these findings in a clinical trial setting.
Source: Medical Xpress
Journal information: Eva Conde et al, Dual vaccination against IL-4 and IL-13 protects against chronic allergic asthma in mice, Nature Communications (2021). DOI: 10.1038/s41467-021-22834-5
