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Marini-Rapoport O, Fernández-Quintero ML, Keswani T, Zong G, Shim J, Pedersen LC, Mueller GA, Patil SU. Defining the cross-reactivity between peanut allergens Ara h 2 and Ara h 6 using monoclonal antibodies. Clin Exp Immunol 2024; 216:25-35. [PMID: 38346116 PMCID: PMC10929694 DOI: 10.1093/cei/uxae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/08/2023] [Accepted: 02/09/2024] [Indexed: 03/13/2024] Open
Abstract
In peanut allergy, Arachis hypogaea 2 (Ara h 2) and Arachis hypogaea 6 (Ara h 6) are two clinically relevant peanut allergens with known structural and sequence homology and demonstrated cross-reactivity. We have previously utilized X-ray crystallography and epitope binning to define the epitopes on Ara h 2. We aimed to quantitatively characterize the cross-reactivity between Ara h 2 and Ara h 6 on a molecular level using human monoclonal antibodies (mAbs) and structural characterization of allergenic epitopes. We utilized mAbs cloned from Ara h 2 positive single B cells isolated from peanut-allergic, oral immunotherapy-treated patients to quantitatively analyze cross-reactivity between recombinant Ara h 2 (rAra h 2) and Ara h 6 (rAra h 6) proteins using biolayer interferometry and indirect inhibitory ELISA. Molecular dynamics simulations assessed time-dependent motions and interactions in the antibody-antigen complexes. Three epitopes-conformational epitopes 1.1 and 3, and the sequential epitope KRELRNL/KRELMNL-are conserved between Ara h 2 and Ara h 6, while two more conformational and three sequential epitopes are not. Overall, mAb affinity was significantly lower to rAra h 6 than it was to rAra h 2. This difference in affinity was primarily due to increased dissociation of the antibodies from rAra h 6, a phenomenon explained by the higher conformational flexibility of the Ara h 6-antibody complexes in comparison to Ara h 2-antibody complexes. Our results further elucidate the cross-reactivity of peanut 2S albumins on a molecular level and support the clinical immunodominance of Ara h 2.
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Affiliation(s)
- Orlee Marini-Rapoport
- Harvard University, Cambridge, MA, USA
- Food Allergy Center, Massachusetts General Hospital, Boston, MA, USA
- Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Boston, MA, USA
| | | | - Tarun Keswani
- Food Allergy Center, Massachusetts General Hospital, Boston, MA, USA
- Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Boston, MA, USA
| | - Guangning Zong
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Jane Shim
- Food Allergy Center, Massachusetts General Hospital, Boston, MA, USA
- Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Boston, MA, USA
| | - Lars C Pedersen
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Geoffrey A Mueller
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Sarita U Patil
- Food Allergy Center, Massachusetts General Hospital, Boston, MA, USA
- Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Boston, MA, USA
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Song M, Zhang Y, Zhu W, Zhou W, Li X, Yang A, Tong P, Wu Z, Chen H. Mass Spectrometry Analysis on the Breakage of Allergens in High-Molecular-Mass Polymer of Roasted Peanuts. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:3142-3149. [PMID: 38299554 DOI: 10.1021/acs.jafc.3c07007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Peanut allergy is a prevalent and concerning food allergy. Roasting can introduce structural changes to peanut allergens, affecting their allergenicity, but the structure on the primary structure is unclear. Here, the breakage sites were identified by mass spectrometry and software tools, and structural changes were simulated by molecular dynamics and displayed by PyMOL software. Results revealed that the appearance frequencies of L, Q, F, and E were high at the N-terminal of the breakage site, while S and E were dominant at the C-terminal. In the conformational structure, breakage sites were found close to disulfide bonds and the Cupin domains of Ara h 1 and Ara h 3. The breakage of allergens destroyed linear epitopes and might change the conformation of epitopes, which could influence peanuts' potential allergenicity.
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Affiliation(s)
- Min Song
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330031, China
- College of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Ying Zhang
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330031, China
- College of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Weichao Zhu
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330031, China
- College of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Wenlong Zhou
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330031, China
- College of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Xin Li
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330031, China
- College of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Anshu Yang
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330031, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Ping Tong
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330031, China
- College of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Zhihua Wu
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330031, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Hongbing Chen
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330031, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
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