Rationally designed hypoallergenic mutant variants of the house dust mite allergen Der p 21

• Published in: Biochimica et biophysica acta. General subjects Vol. 1866; no. 4; p. 130096
• Main Authors: Santos, Sara P.O., Lisboa, Ayrton B.P., Silva, Filipe S.R., Tiwari, Sandeep, Azevedo, Vasco, Cruz, Álvaro A., Silva, Eduardo S., Pinheiro, Carina S., Alcantara-Neves, Neuza M., Pacheco, Luis G.C.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2022
• Subjects: Allergen engineering; Allergen-specific immunotherapy; allergens; Allergens - genetics; amino acids; Animals; Antigens, Dermatophagoides - chemistry; Antigens, Dermatophagoides - genetics; Arthropod Proteins - genetics; computer simulation; Der p 21; Dermatophagoides pteronyssinus; dust mites; epitopes; Humans; Hypersensitivity - genetics; immune response; Immunoglobulin E - genetics; Immunoinformatics; immunotherapy; mutagenesis; mutants; Pyroglyphidae - genetics; Pyroglyphidae - metabolism; Recombinant hypoallergen; Der p 21; Allergen-specific immunotherapy; Recombinant hypoallergen; Allergen engineering; Dermatophagoides pteronyssinus; Immunoinformatics
• ISSN: 0304-4165; 1872-8006; 1872-8006
• DOI: 10.1016/j.bbagen.2022.130096

Allergic diseases figure among the most common immune-mediated diseases worldwide, affecting more than 25% of the world's population. Allergic reactions can be triggered by house dust mite (HDM) allergens, of which the so-called group 21 of allergens is considered as clinically relevant. Herein, we used a structural bioinformatics and immunoinformatics approach to design hypoallergenic mutant variants of the Der p 21 allergen of Dermatophagoides pteronyssinus, which were then recombinantly expressed in bacteria and tested for their IgE-reactivities. For this, we scanned the wild-type Der p 21 protein for all possible single amino acid substitutions in key IgE-binding regions that could render destabilization of the major epitope regions. Four main substitutions (D82P, K110G, E77G, and E87S) were selected to build mutant variants of the Der p 21 allergen, which were produced in their recombinant forms; two of these variants showed reduced reactivity with IgE. Molecular dynamic simulations and immune simulations demonstrated the overall effects of these mutations on the structural stability of the Der p 21 allergen and on the profile of immune response induced through immunotherapy. When produced in their recombinant forms, two of the Der p 21 mutant variants, namely proteins K110G and E87S, showed significantly reduced IgE reactivities against sera from HDM-allergic individuals (n = 20; p < 0.001). This study successfully translated a rational in silico mutagenesis design into low IgE-binding mutant variants of the allergen rDer p 21. These novel hypoallergens are promising to compose next-generation allergen-immunotherapy formulations in near future. •IgE-mediated allergic reactions affect a significantly high proportion of the world population.•Hypoallergens represent a promising alternative for safer and more effective immunotherapy.•Protein engineering can be used to produce hypoallergenic mutant derivatives of major allergens.•Through a rational in silico mutagenesis design we developed hypoallergenic variants of Der p 21.