Nanobody-based Inhibitors of Allergen-mediated Anaphylaxis

Research output: Book/anthology/dissertation/reportPh.D. thesis

Abstract

Hymenoptera venom allergy is one of the most common causes of anaphylaxis. The allergic reaction is induced by an insect sting and is caused by the binding of venom allergens to allergen-specific IgE antibodies and the subsequent activation of effector cells.

In order to block the allergic reaction and reduce the risk of anaphylaxis in Hymenoptera venom-allergic patients, this project aimed to establish nanobody-based molecules that can block the interaction between the most dominant allergens from insect venom and allergen-specific IgE from allergic patients. Therefore, nanobodies against the major honeybee venom
allergen Api m 1 were selected. The selection was performed by phage display using an immune library and resulted in the successful selection of a panel of Api m 1-specific nanobodies. Characterizations of the nanobody/allergen interactions enabled the identification of two high-affinity lead nanobodies with non-overlapping epitopes. Crystal structures of these nanobodies in complex with Api m 1 revealed binding to two diametrically opposed epitopes and provided insights into the structural basis for their inhibitory properties. For therapeutic use, mono- and bi-specific nanobody-human IgG1 Fc formats were developed. These nanobody-based molecules demonstrated pronounced blocking of IgE binding and reduced the subsequent activation of effector cells in honeybee venom allergic patients. Thus, the project provides the basis for establishing a passive immunotherapy approach in honeybee venom allergy using nanobody-based inhibitors.

In order to further strengthen the concept, a second selection of nanobodies against Api m 1 was performed, this time using an antibody-guided strategy. Initial characterization of the new nanobodies suggested an increased blocking efficiency of one of the nanobodies. Furthermore, nanobodies against the major allergens Ves v 1 and Ves v 5 from yellow jacket venom were selected. These nanobodies will form the basis for translating the concept to wasp venom allergy.

In addition to the blocking nanobody-based IgG formats, novel allergen-specific nanobody-based human IgE formats were established for standardization purposes in diagnostics. These IgE surrogates were compatible with diagnostic test systems and could potentially improve the quality and accuracy of the test systems.

In conclusion, the work presented in this dissertation demonstrates the applicability of allergen-specific nanobody-based molecules in diagnostics and as potential therapeutics for a passive immunotherapy concept in the context of Hymenoptera venom allergy.
Original languageEnglish
PublisherÅrhus Universitet
Number of pages153
Publication statusPublished - Oct 2023

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