Two-Allergen Model Reveals Complex Relationship between IgE Crosslinking and Degranulation

Handlogten, Michael W.; Deak, Peter E.; Bilgiçer, Başar

doi:10.1016/j.chembiol.2014.08.019

Cited by 9 publications

(14 citation statements)

References 20 publications

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“…Given that patients generate IgE to multiple proteins and multiple epitopes within each protein, the inhibition of responses by only two epitopes highlights that we still know very little about engagement of IgE by complex allergens. In our previous work we demonstrated that low-affinity epitopes can cooperate with high-affinity epitopes in IgE engagement and degranulation responses (32). Moreover, we previously observed that certain peanut epitopes trigger degranulation at significantly lower concentrations of nanoallergens, but when used in combination with an epitope of lower potency, there is a synergistic enhancement of degranulation (12).…”

Section: Discussionmentioning

confidence: 97%

“…Percent degranulation was calculated as previously decribed (32). Briefly, experimental signals were calculated as a percentage between positive control (100%) and negative control (0%).…”

Section: Methodsmentioning

confidence: 99%

“…Mice were maintained in pathogen-free conditions, and studies were approved by the Indiana University Institutional Animal Care and Use Committee. Toxicology studies were carried out in a similar manner as previously published in the University of Indiana In Vivo Therapeutics Core (32). Basophil activation test.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Designer covalent heterobivalent inhibitors prevent IgE-dependent responses to peanut allergen

Deak

Kim

Qayum

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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Allergies are a result of allergen proteins cross-linking allergen-specific IgE (sIgE) on the surface of mast cells and basophils. The diversity and complexity of allergen epitopes, and high-affinity of the sIgE–allergen interaction have impaired the development of allergen-specific inhibitors of allergic responses. This study presents a design of food allergen-specific sIgE inhibitors named covalent heterobivalent inhibitors (cHBIs) that selectively form covalent bonds to only sIgEs, thereby permanently inhibiting them. Using screening reagents termed nanoallergens, we identified two immunodominant epitopes in peanuts that were common in a population of 16 allergic patients. Two cHBIs designed to inhibit only these two epitopes completely abrogated the allergic response in 14 of the 16 patients in an in vitro assay and inhibited basophil activation in an allergic patient ex vivo analysis. The efficacy of the cHBI design has valuable clinical implications for many allergen-specific responses and more broadly for any antibody-based disease.

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Section: Discussionmentioning

confidence: 97%

“…Percent degranulation was calculated as previously decribed (32). Briefly, experimental signals were calculated as a percentage between positive control (100%) and negative control (0%).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Designer covalent heterobivalent inhibitors prevent IgE-dependent responses to peanut allergen

Deak

Kim

Qayum

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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“…12–15 Likewise, in our laboratory, we have demonstrated the importance of weaker affinity epitope during the degranulation response. 16,17 …”

Section: Introductionmentioning

confidence: 99%

Nanoallergens: A multivalent platform for studying and evaluating potency of allergen epitopes in cellular degranulation

Deak

Vrabel

Pizzuti

et al. 2016

Exp Biol Med (Maywood)

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Degranulation caused by type I hypersensitivity (allergies) is a complex biophysical process, and available experimental models for studying relevant immunoglobulin E (IgE) binding epitopes on allergen proteins lack the ability to adequately evaluate, rank and associate these epitopes individually and with each other. In this study, we propose a new allergy model system for studying potential allergen epitopes using nanoallergens, liposomes modified to effectively display IgE binding epitopes/haptens. By utilizing the covalently conjugated lipid tails on two hapten molecules (dinitrophenol and dansyl), hapten molecules were successfully incorporated into liposomes with high precision to form nanoallergens. Nanoallergens, with precisely controlled high particle valency, can trigger degranulation with much greater sensitivity than commonly used bovine serum albumin (BSA) conjugates. In Rat Basophil Leukemia (RBL) cell experiments, nanoallergens with only 2% hapten loading were able to trigger degranulation in vitro at concentrations as low as 10 pM. Additionally, unlike BSA-hapten conjugates, nanoallergens allow exact control over particle size and valency. By varying the nanoallergen parameters such as size, valency, monovalent affinity of hapten, and specific IgE ratios, we exposed the importance of these variables on degranulation intensity while demonstrating nanoallergens’ potential for evaluating both high and low affinity epitopes. The data presented in this article establish nanoallergen platform as a reliable and versatile allergy model to study and evaluate allergen epitopes in mast cell degranulation.

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“…One well-characterized system is the hapten/Ab pair DNP/anti-DNP IgE. In these systems, small synthetic allergens are often conjugated to a carrier protein, such as BSA (13), a synthetic scaffold (14)(15)(16)(17), or incorporated into liposomes (18). Alternatively, artificial allergens have been generated by grafting IgE epitopes onto a scaffold protein in different numbers and spacings (19).…”

mentioning

confidence: 99%

Interplay between Affinity and Valency in Effector Cell Degranulation: A Model System with Polcalcin Allergens and Human Patient–Derived IgE Antibodies

Bucaite

Kang-Pettinger

Moreira

et al. 2019

The Journal of Immunology

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An allergic reaction is rapidly generated when allergens bind and cross-link IgE bound to its receptor Fc«RI on effector cells, resulting in cell degranulation and release of proinflammatory mediators. The extent of effector cell activation is linked to allergen affinity, oligomeric state, valency, and spacing of IgE-binding epitopes on the allergen. Whereas most of these observations come from studies using synthetic allergens, in this study we have used Timothy grass pollen allergen Phl p 7 and birch pollen allergen Bet v 4 to study these effects. Despite the high homology of these polcalcin family allergens, Phl p 7 and Bet v 4 display different binding characteristics toward two human patient-derived polcalcin-specific IgE Abs. We have used native polcalcin dimers and engineered multimeric allergens to test the effects of affinity and oligomeric state on IgE binding and effector cell activation. Our results indicate that polcalcin multimers are required to stimulate high levels of effector cell degranulation when using the humanized RBL-SX38 cell model and that multivalency can overcome the need for high-affinity interactions.

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Two-Allergen Model Reveals Complex Relationship between IgE Crosslinking and Degranulation

Cited by 9 publications

References 20 publications

Designer covalent heterobivalent inhibitors prevent IgE-dependent responses to peanut allergen

Designer covalent heterobivalent inhibitors prevent IgE-dependent responses to peanut allergen

Nanoallergens: A multivalent platform for studying and evaluating potency of allergen epitopes in cellular degranulation

Interplay between Affinity and Valency in Effector Cell Degranulation: A Model System with Polcalcin Allergens and Human Patient–Derived IgE Antibodies

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