Allergen hybrids - next generation vaccines for Fagales pollen immunotherapy

作者：Pichler U; Hauser M; Hofer H; Himly M; Hoflehner E; Steiner M; Mutschlechner S; Hufnagl K; Ebner C; Mari A; Briza P; Bohle B; Wiedermann U; Ferreira F; Wallner M^*

来源：Clinical and Experimental Allergy, 2014, 44(3): 438-449.

DOI：10.1111/cea.12250

• allergen-specific immunotherapy
• birch pollen allergy
• Fagales pollen allergy
• hybrid protein
• immunomodulation
• protein remodelling

BackgroundTrees belonging to the order of Fagales show a distinct geographical distribution. While alder and birch are endemic in the temperate zones of the Northern Hemisphere, hazel, hornbeam and oak prefer a warmer climate. However, specific immunotherapy of Fagales pollen-allergic patients is mainly performed using birch pollen extracts, thus limiting the success of this intervention in birch-free areas. %26lt;br%26gt;ObjectivesT cells are considered key players in the modification of an allergic immune response during specific immunotherapy (SIT), therefore we thought to combine linear T cell epitope-containing stretches of the five most important Fagales allergens from birch, hazel, alder, oak and hornbeam resulting in a Fagales pollen hybrid (FPH) molecule applicable for SIT. %26lt;br%26gt;MethodsA Fagales pollen hybrid was generated by PCR-based recombination of low IgE-binding allergen epitopes. Moreover, a structural-variant FPH4 was calculated by in silico mutagenesis, rendering the protein unable to adopt the Bet v 1-like fold. Both molecules were produced in Escherichia coli, characterized physico-chemically as well as immunologically, and tested in mouse models of allergic sensitization as well as allergy prophylaxis. %26lt;br%26gt;ResultsUsing spectroscopic analyses, both proteins were monomeric, and the secondary structure elements of FPH resemble the ones typical for Bet v 1-like proteins, whereas FPH4 showed increased amounts of unordered structure. Both molecules displayed reduced binding capacities of Bet v 1-specific IgE antibodies. However, in a mouse model, the proteins were able to induce high IgG titres cross-reactive with all parental allergens. Moreover, prophylactic treatment with the hybrid proteins prevented pollen extract-induced allergic lung inflammation in vivo. %26lt;br%26gt;ConclusionThe hybrid molecules showed a more efficient uptake and processing by dendritic cells resulting in a modified T cell response. The proteins had a lower IgE-binding capacity compared with the parental allergens, thus the high safety profile and increased efficacy emphasize clinical application for the treatment of Fagales multi-sensitization.

• 出版日期2014-3