A novel bispecific DARPin targeting FcγRIIB and FcεRI-bound IgE inhibits allergic responses

Zellweger, F.; Gasser, P.; Brigger, Daniel; Buschor, P.; Vogel, Monique; Eggel, Alexander (2017). A novel bispecific DARPin targeting FcγRIIB and FcεRI-bound IgE inhibits allergic responses. Allergy, 72(8), pp. 1174-1183. Wiley-Blackwell 10.1111/all.13109

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BACKGROUND: Binding of allergen-specific IgE to its high-affinity receptor FcεRI on basophils and mast cells is a central event in the development of allergies. Exposure of these cells to allergens induces the release of soluble mediators causing allergic symptoms. The inhibitory low-affinity IgG Fc-receptor FcγRIIB is co-expressed on allergic effector cells and has been implicated in negative regulation of immediate hypersensitivity responses. In order to harvest the inhibitory function of this receptor, we aimed to select specific binders against FcγRIIB and to generate a bispecific molecule simultaneously targeting FcγRIIB and FcεRI-bound IgE on the surface of allergic effector cells. METHODS: We selected FcγRIIB-specific binding molecules from a library of designed ankyrin repeat proteins using ribosome display technology. The bispecific binding modality was generated by molecular cloning and recombinant protein expression. We determined binding characteristics on molecular and cellular levels using SPR, ELISA, and flow cytometry. The inhibitory potential of the newly described molecules was assessed in different cellular degranulation assays ex vivo and in a mouse model of passive systemic anaphylaxis. RESULTS: We demonstrate that the selected DARPin® proteins recognize FcγRIIB with high affinity. Furthermore, the bispecific binding protein successfully interferes with allergen-induced cell degranulation and efficiently inhibits systemic anaphylaxis in vivo. Mechanistically, we report that FcγRIIB-mediated inhibition of effector cell activation requires direct ligation to an activating FcεRI receptor. CONCLUSION: The described bispecific DARPin protein has the ability to co-ligate FcγRIIB with FcεRI-bound IgE on allergic effector cells and represents an efficient dual-modality to interfere with allergic hypersensitivity reactions.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Institute for Immunology (discontinued)
04 Faculty of Medicine > Department of Dermatology, Urology, Rheumatology, Nephrology, Osteoporosis (DURN) > Clinic of Rheumatology, Clinical Immunology and Allergology

UniBE Contributor:

Brigger, Daniel; Vogel, Monique and Eggel, Alexander

Subjects:

600 Technology > 610 Medicine & health

ISSN:

0105-4538

Publisher:

Wiley-Blackwell

Language:

English

Submitter:

Eveline Messerli

Date Deposited:

14 Mar 2017 11:07

Last Modified:

12 Jul 2017 01:35

Publisher DOI:

10.1111/all.13109

PubMed ID:

27997998

Uncontrolled Keywords:

FcγRIIb; FcεRIα; IgE; allergy; bispecific DARPin

BORIS DOI:

10.7892/boris.94953

URI:

https://boris.unibe.ch/id/eprint/94953

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