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Barshow SM, Islam M, Commins S, Macauley MS, Paulson JC, Kulis MD. Targeting inhibitory Siglec-3 to suppress IgE-mediated human basophil degranulation. J Allergy Clin Immunol 2024:S0091-6749(24)00332-4. [PMID: 38593870 DOI: 10.1016/j.jaci.2024.03.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/12/2024] [Accepted: 03/08/2024] [Indexed: 04/11/2024]
Abstract
BACKGROUND Sialic acid-binding immunoglobulin-like lectin-3 (Siglec-3 [CD33]) is a major Siglec expressed on human mast cells and basophils; engagement of CD33 leads to inhibition of cellular signaling via immunoreceptor tyrosine-based inhibitory motifs. OBJECTIVE We sought to inhibit human basophil degranulation by simultaneously recruiting inhibitory CD33 to the IgE-FcεRI complex by using monoclonal anti-IgE directly conjugated to CD33 ligand (CD33L). METHODS Direct and indirect basophil activation tests (BATs) were used to assess both antigen-specific (peanut) and antigen-nonspecific (polyclonal anti-IgE) stimulation. Whole blood from donors with allergy was used for direct BAT, whereas blood from donors with nonfood allergy was passively sensitized with plasma from donors with peanut allergy in the indirect BAT. Blood was incubated with anti-IgE-CD33L or controls for 1 hour or overnight and then stimulated with peanut, polyclonal anti-IgE, or N-formylmethionyl-leucyl-phenylalanine for 30 minutes. Degranulation was determined by measuring CD63 expression on the basophil surface by flow cytometry. RESULTS Incubation for 1 hour with anti-IgE-CD33L significantly reduced basophil degranulation after both allergen-induced (peanut) and polyclonal anti-IgE stimulation, with further suppression after overnight incubation with anti-IgE-CD33L. As expected, anti-IgE-CD33L did not block basophil degranulation due to N-formylmethionyl-leucyl-phenylalanine, providing evidence that this inhibition is IgE pathway-specific. Finally, CD33L is necessary for this suppression, as monoclonal anti-IgE without CD33L was unable to reduce basophil degranulation. CONCLUSIONS Pretreating human basophils with anti-IgE-CD33L significantly suppressed basophil degranulation through the IgE-FcεRI complex. The ability to abrogate IgE-mediated basophil degranulation is of particular interest, as treatment with anti-IgE-CD33L before antigen exposure could have broad implications for the treatment of food, drug, and environmental allergies.
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Affiliation(s)
- Suzanne M Barshow
- Duke University School of Medicine, Durham, NC; University of North Carolina at Chapel Hill, Chapel Hill, NC
| | | | - Scott Commins
- University of North Carolina at Chapel Hill, Chapel Hill, NC
| | | | | | - Michael D Kulis
- University of North Carolina at Chapel Hill, Chapel Hill, NC.
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2
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O'Konek JJ. Animal Models in the Study of Food Allergens: Long-Term Maintenance of Allergic Reactivity in Mouse Models of Food Allergy. Methods Mol Biol 2024; 2717:321-335. [PMID: 37737995 DOI: 10.1007/978-1-0716-3453-0_22] [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] [Indexed: 09/23/2023]
Abstract
Multiple mouse models have been used to characterize mechanisms of allergic sensitization and anaphylaxis and are widely used for preclinical development of novel therapeutics. However, the majority of published works with mouse models of food allergy have very short intervals between the time of sensitization and the end of the study, and the duration of maintenance of reactivity has not been widely reported. This chapter focuses on two of the most commonly used mouse models with sensitization to peanut or ovalbumin, with the focus on the long-term durability of sensitization to allow for longer therapeutic protocols and assessment of sustained unresponsiveness.
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Affiliation(s)
- Jessica J O'Konek
- Mary H. Weiser Food Allergy Center, University of Michigan, Ann Arbor, MI, USA.
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Chen Q, Liu H, Luling N, Reinke J, Dent AL. Evidence that High-Affinity IgE Can Develop in the Germinal Center in the Absence of an IgG1-Switched Intermediate. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:905-915. [PMID: 36779803 PMCID: PMC10038918 DOI: 10.4049/jimmunol.2200521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 01/12/2023] [Indexed: 02/14/2023]
Abstract
High-affinity allergen-specific IgE is essential for the severe allergic anaphylaxis response. High-affinity Abs are formed by successive rounds of selection of Ag-specific B cells in the germinal center (GC); however, several studies have shown that IgE+ GC B cells are impaired in their ability to undergo selection in the GC. A pathway, known as the "indirect switching pathway" for IgE, has been described whereby Ag-specific B cells initially switch to the IgG1 isotype and undergo affinity selection in the GC, with a secondary switch to the IgE isotype after affinity selection. In previous work, using a food allergy model in mice, we investigated how high-affinity IgE develops in the GC, but we did not test the indirect switching model. In this study, we analyzed the importance of the indirect switching pathway by constructing IgG1-cre Bcl6-fl/fl mice. In these mice, once B cells switch to IgG1, they delete Bcl6 and thus cannot enter or persist in the GC. When we tested IgG1-cre Bcl6-fl/fl mice with our food allergy model, we found that, as expected, IgG1 Abs had decreased affinity, but unexpectedly, the affinity of IgE for allergen was unchanged. IgG1-cre Bcl6-fl/fl mice underwent anaphylaxis in response to allergen, consistent with the formation of high-affinity IgE. Thus, in a food allergy response, high-affinity IgE can be efficiently formed in the absence of indirect switching to IgG1, either by direct selection of IgE+ GC B cells or indirect selection of IgM+ GC B cells that later switch to IgE.
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Affiliation(s)
- Qiang Chen
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN
| | - Hong Liu
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN
| | - Noelle Luling
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN
| | - Julia Reinke
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN
| | - Alexander L Dent
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN
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4
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Peach extract induces systemic and local immune responses in an experimental food allergy model. Sci Rep 2023; 13:1892. [PMID: 36732575 PMCID: PMC9894845 DOI: 10.1038/s41598-023-28933-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Peach allergy is among the most frequent food allergies in the Mediterranean area, often eliciting severe anaphylactic reactions in patients. Due to the risk of severe symptoms, studies in humans are limited, leading to a lack of therapeutic options. This study aimed to develop a peach allergy mouse model as a tool to better understand the pathomechanism and to allow preclinical investigations on the development of optimized strategies for immunotherapy. CBA/J mice were sensitized intraperitoneally with peach extract or PBS, using alum as adjuvant. Afterwards, extract was administered intragastrically to involve the intestinal tract. Allergen provocation was performed via intraperitoneal injection of extract, measuring drop of body temperature as main read out of anaphylaxis. The model induced allergy-related symptoms in mice, including decrease of body temperature. Antibody levels in serum and intestinal homogenates revealed a Th2 response with increased levels of mMCPT-1, peach- and Pru p 3-specific IgE, IgG1 and IgG2a as well as increased levels of IL-4 and IL-13. FACS analysis of small intestine lamina propria revealed increased amounts of T cells, neutrophils and DCs in peach allergic mice. These data suggest the successful establishment of a peach allergy mouse model, inducing systemic as well as local gastrointestinal reactions.
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5
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Chen Q, Xie M, Liu H, Dent AL. Development of allergen-specific IgE in a food-allergy model requires precisely timed B cell stimulation and is inhibited by Fgl2. Cell Rep 2022; 39:110990. [PMID: 35767958 PMCID: PMC9271337 DOI: 10.1016/j.celrep.2022.110990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 04/12/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022] Open
Abstract
Immunoglobulin E (IgE) responses are a central feature of allergic disease. Using a well-established food-allergy model in mice, we show that two sensitizations with cognate B cell antigen (Ag) and adjuvant 7 days apart promotes optimal development of IgE+ germinal center (GC) B cells and high-affinity IgE production. Intervals of 3 or 14 days between Ag sensitizations lead to loss of IgE+ GC B cells and an undetectable IgE response. The immunosuppressive factors Fgl2 and CD39 are down-regulated in T follicular helper (TFH) cells under optimal IgE-sensitization conditions. Deletion of Fgl2 in TFH and T follicular regulatory (TFR) cells, but not from TFR cells alone, increase Ag-specific IgE levels and IgE-mediated anaphylactic responses. Overall, we find that Ag-specific IgE responses require precisely timed stimulation of IgE+ GC B cells by Ag. Furthermore, we show that Fgl2 is expressed by TFH cells and represses IgE. This work has implications for the development and treatment of food allergies. Using a mouse food-allergy model, Chen et al. find that allergen-specific IgE responses require precisely timed stimulation of IgE+ germinal center B cells. The authors further show that Fgl2 expressed by T follicular helper cells represses IgE. This work has implications for the development and treatment of food allergy.
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Affiliation(s)
- Qiang Chen
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Markus Xie
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Hong Liu
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Alexander L Dent
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA.
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Landers JJ, Janczak KW, Shakya AK, Zarnitsyn V, Patel SR, Baker JR, Gill HS, O'Konek JJ. Targeted allergen-specific immunotherapy within the skin improves allergen delivery to induce desensitization to peanut. Immunotherapy 2022; 14:539-552. [PMID: 35196877 PMCID: PMC9043875 DOI: 10.2217/imt-2021-0206] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 01/26/2022] [Indexed: 11/21/2022] Open
Abstract
Aim: Epicutaneous immunotherapy (EPIT) with peanut has been demonstrated to be safe but efficacy may be limited by allergen uptake through the skin barrier. To enhance allergen uptake into the skin, the authors used peanut-coated microneedles and compared them with EPIT in a peanut allergy mouse model. Methods: Sensitized mice were treated with peanut-coated microneedles or peanut-EPIT and then challenged with peanut to determine protection. Results: Treatment with peanut-coated microneedles was safe and showed enhanced desensitization to peanut compared with peanut-EPIT administered via a similar schedule. Protection was associated with reduced Th2 immune responses and mast cell accumulation in the intestine. Conclusion: Peanut-coated microneedles have the potential to present a safe method of improving allergen delivery for cutaneous immunotherapy.
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Affiliation(s)
- Jeffrey J Landers
- Mary H. Weiser Food Allergy Center, University of Michigan, Ann Arbor, MI 48109, USA
| | - Katarzyna W Janczak
- Mary H. Weiser Food Allergy Center, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | | | - James R Baker
- Mary H. Weiser Food Allergy Center, University of Michigan, Ann Arbor, MI 48109, USA
| | - Harvinder Singh Gill
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Jessica J O'Konek
- Mary H. Weiser Food Allergy Center, University of Michigan, Ann Arbor, MI 48109, USA
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Krempski JW, Lama JK, Iijima K, Kobayashi T, Matsunaga M, Kita H. A Mouse Model of the “LEAP” Study Reveals a Role for CTLA-4 in Preventing Peanut Allergy Induced by Environmental Peanut Exposure. J Allergy Clin Immunol 2022; 150:425-439.e3. [PMID: 35288169 PMCID: PMC9378358 DOI: 10.1016/j.jaci.2022.02.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/10/2022] [Accepted: 02/03/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND A human study, Learning Early About Peanut Allergy (LEAP), showed that early introduction of peanut products decreases the prevalence of peanut allergy among children. However, the immunologic mechanisms mediating the protective effects of consuming peanut products are not well understood. OBJECTIVE The objective was to develop a mouse model that simulates the LEAP study and investigate the underlying mechanisms for the study observations. METHODS Adult naive BALB/c mice were fed a commercial peanut butter product (Skippy) or buffer control and concomitantly exposed to peanut flour through the airway or skin to mimic environmental exposure. The animals were analyzed for anaphylactic reaction and by molecular and immunologic approaches. RESULTS After exposure to peanut flour through the airway or skin, naive mice developed peanut allergy, as demonstrated by acute and systemic anaphylaxis in response to challenge with peanut extract. Ingestion of Skippy, however, nearly abolished the increase in peanut-specific IgE and IgG and protected animals from developing anaphylaxis. Skippy-fed mice showed reduced numbers of T follicular helper (Tfh) cells and germinal center B cells in their draining lymph nodes, and single-cell RNA sequencing revealed a CD4+ T-cell population expressing cytotoxic T lymphocyte-associated protein 4 (CTLA-4) in these animals. Critically, blocking CTLA-4 with antibody increased levels of peanut-specific antibodies and reversed the protective effects of Skippy. CONCLUSION Ingestion of a peanut product protects mice from peanut allergy induced by environmental exposure to peanuts, and the CTLA-4 pathway, which regulates Tfh cell responses, likely plays a pivotal role in this protection.
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Camilleri AE, Nag S, Russo AR, Stiles KM, Crystal RG, Pagovich OE. Gene therapy for a murine model of eosinophilic esophagitis. Allergy 2021; 76:2740-2752. [PMID: 33748982 DOI: 10.1111/all.14822] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/05/2021] [Accepted: 01/15/2021] [Indexed: 01/07/2023]
Abstract
BACKGROUND Eosinophils are specialized granulocytic effector cells that store and release highly active mediators used in immune defense. Eosinophils are also implicated in the pathogenesis of allergic disorders, including eosinophilic esophagitis (EoE), a chronic disorder characterized by infiltration of eosinophils into the esophagus and release of mediators that damage tissue, resulting in gastrointestinal morbidity, food impaction, and dysphagia. Treatment with elimination diets and/or topical corticosteroid therapy slow disease progression, but are complicated by adverse effects, limited compliance, and loss of response to therapy. We hypothesized that a single administration of an adeno-associated virus (AAV) coding for an anti-eosinophil monoclonal antibody that induces eosinophil clearance (anti-Siglec-F) would treat on a persistent basis a murine model of EoE. METHODS A mouse model of peanut-induced EoE that mimics the human disease was established by sensitization and challenge with peanut extract. After challenge, these mice exhibited an EoE phenotype demonstrated by elevated levels of blood eosinophils, infiltration of eosinophils in the esophagus with associated esophageal remodeling and food impaction. RESULTS The mice were treated with a single intravenous administration (1011 genome copies) of AAVrh.10mAnti-Eos, a serotype rh.10 AAV vector coding for an anti-Siglec-F monoclonal antibody. Vector administration resulted in persistent, high levels of anti-Siglec-F antibody expression. Administration of AAVrh.10mAnti-Eos to the mouse model of EoE reduced blood (P < 0.02) and esophageal eosinophil numbers (P < 0.002) protected from esophageal tissue remodeling and minimized food impaction. CONCLUSION These results suggest that a single treatment with AAVrh.10mAnti-Eos has the potential to provide persistent therapeutic benefit to patients with EoE.
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Affiliation(s)
- Anna E. Camilleri
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Saparja Nag
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Anthony R. Russo
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Katie M. Stiles
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Ronald G. Crystal
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Odelya E. Pagovich
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
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9
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Zhou C, Chen LL, Lu RQ, Ma WW, Xiao R. Alteration of Intestinal Microbiota Composition in Oral Sensitized C3H/HeJ Mice Is Associated With Changes in Dendritic Cells and T Cells in Mesenteric Lymph Nodes. Front Immunol 2021; 12:631494. [PMID: 34177885 PMCID: PMC8222730 DOI: 10.3389/fimmu.2021.631494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 04/12/2021] [Indexed: 12/14/2022] Open
Abstract
This research aimed to investigate the allergic reaction of C3H/HeJ mice after sensitization with ovalbumin (OVA) without any adjuvant and to analyze the association between intestinal microbiota and allergy-related immune cells in mesenteric lymph nodes (MLN). The allergic responses of C3H/HeJ mice orally sensitized with OVA were evaluated, and immune cell subsets in spleen and MLN and cytokines were also detected. The intestinal bacterial community structure was analyzed, followed by Spearman correlation analysis between changed gut microbiota species and allergic parameters. Sensitization induced a noticeable allergic response to the gavage of OVA without adjuvant. Increased levels of Th2, IL-4, CD103+CD86+ DC, and MHCII+CD86+ DC and decreased levels of Th1, Treg, IFN-γ, TGF-β1, and CD11C+CD103+ DC were observed in allergic mice. Furthermore, families of Lachnospiraceae, Clostridiaceae_1, Ruminococcaceae, and peprostreptococcaceae, all of which belonging to the order Clostridiales, were positively related to Treg and CD11C+CD103+ DC, while they were negatively related to an allergic reaction, levels of Th2, CD103+CD86+ DC, and MHCII+CD86+ DC in MLN. The family of norank_o_Mollicutes_RF39 belonging to the order Mollicutes_RF39 was similarly correlated with allergic reaction and immune cells in MLN of mice. To sum up, allergic reactions and intestinal flora disturbances could be induced by OVA oral administration alone. The orders of Clostridiales and Mollicutes_RF39 in intestinal flora are positively correlated with levels of Treg and CD11C+CD103+ DC in MLN of mice.
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Affiliation(s)
- Cui Zhou
- Beijing Key Laboratory of Environmental Toxicology, School of Public Health, Capital Medical University, Beijing, China
| | - Ling-Ling Chen
- Nutritional Department, Handan First Hospital, Handan, China
| | - Rui-Qi Lu
- School of Basic Medicine, Capital Medical University, Beijing, China
| | - Wei-Wei Ma
- Beijing Key Laboratory of Environmental Toxicology, School of Public Health, Capital Medical University, Beijing, China
| | - Rong Xiao
- Beijing Key Laboratory of Environmental Toxicology, School of Public Health, Capital Medical University, Beijing, China
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Kulis MD, Smeekens JM, Kavanagh K, Jorgensen MJ. Peanut applied to the skin of nonhuman primates induces antigen-specific IgG but not IgE. IMMUNITY INFLAMMATION AND DISEASE 2020; 8:211-215. [PMID: 32220059 PMCID: PMC7212195 DOI: 10.1002/iid3.296] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 01/23/2020] [Accepted: 02/25/2020] [Indexed: 02/02/2023]
Abstract
Introduction Previous studies in humans support the dual‐allergen exposure hypothesis, and several studies in mouse models have demonstrated that cutaneous exposure to disrupted or intact skin can lead to sensitization to peanut. However, the field lacks definitive evidence that cutaneous exposure leads to peanut allergy in humans or other primates. Methods Peanut extract was applied to the shaved back of the neck of four male and four female African green monkeys three times per week for 4 weeks. An oral food challenge (OFC) was performed the following week by gavage of 200 mg of peanut protein, and vital signs were monitored for 30 minutes post‐OFC. Blood was collected at baseline, day 11, day 32, and 30 minutes post‐OFC. Total IgE, and peanut‐specific immunoglobulin E (IgE) and immunoglobulin G (IgG) were quantified in serum collected throughout the 4 weeks. Histamine was measured in serum collected 30 minutes post‐OFC. Results Peanut‐specific IgE was undetectable at any time points in any of the monkeys, and there was no consistent increase in total IgE. During the oral challenge, none of the monkeys experienced allergic symptoms and histamine levels did not change. However, seven of the eight monkeys produced increasing peanut‐specific IgG by day 32, indicating that repeated skin exposure to peanut is immunogenic. Conclusions Skin exposure to peanut did not lead to sensitization in this study, and monkeys did not experience anaphylaxis upon peanut challenge. However, monkeys produced increased peanut‐specific IgG throughout peanut exposure, indicating that repeated skin exposure to peanut is immunogenic.
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Affiliation(s)
- Michael D Kulis
- Division of Allergy, Immunology, and Rheumatology, Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina.,Department of Pediatrics, University of North Carolina Food Allergy Initiative, University of North Carolina, Chapel Hill, North Carolina
| | - Johanna M Smeekens
- Division of Allergy, Immunology, and Rheumatology, Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina.,Department of Pediatrics, University of North Carolina Food Allergy Initiative, University of North Carolina, Chapel Hill, North Carolina
| | - Kylie Kavanagh
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina.,Department of Biomedicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Matthew J Jorgensen
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
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Orgel K, Burk C, Smeekens J, Suber J, Hardy L, Guo R, Burks AW, Kulis M. Blocking antibodies induced by peanut oral and sublingual immunotherapy suppress basophil activation and are associated with sustained unresponsiveness. Clin Exp Allergy 2018; 49:461-470. [PMID: 30383313 PMCID: PMC6438743 DOI: 10.1111/cea.13305] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 10/10/2018] [Accepted: 10/15/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND Oral and sublingual immunotherapies for peanut allergy have demonstrated efficacy in small clinical trials; however, mechanisms and biomarkers correlating with clinical outcomes remain elusive. Previous studies have demonstrated a role for IgG in post-OIT plasma in the suppression of IgE-mediated mast cell reactions. OBJECTIVE The aim of this study was to characterize the role that peanut oral and sublingual immunotherapy-induced plasma factors play in the inhibition of ex vivo basophil activation and whether inhibitory activity is associated with clinical outcomes. METHODS Plasma samples from subjects on placebo, peanut oral immunotherapy (OIT) or peanut sublingual immunotherapy (SLIT), and IgG-depleted plasma or the IgG fraction were incubated with sensitized basophils, and the inhibition of basophil activation following stimulation with peanut extract was measured. Basophil inhibition results were compared between the two routes of immunotherapy, time on treatment and clinical outcomes. RESULTS Plasma from subjects after 12 months of active peanut OIT, but not placebo, inhibits basophil activation ex vivo. Depletion of IgG abrogated the blocking effect of OIT plasma, while the IgG fraction substantially blocked basophil activation. Basophils are inhibited to a similar extent by undiluted OIT and SLIT plasma; however, diluted OIT plasma from the time of desensitization challenge inhibited basophils more than diluted SLIT plasma from time of desensitization challenge. Plasma from subjects who experienced sustained unresponsiveness following OIT inhibited basophils to a greater extent than plasma from subjects who were desensitized, but this was not true for SLIT. CONCLUSIONS AND CLINICAL RELEVANCE Peanut immunotherapy induces IgG-dependent functional changes in plasma that are associated with OIT but not SLIT clinical outcomes. Understanding the mechanisms of peanut OIT and SLIT may help derive informative biomarkers.
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Affiliation(s)
- Kelly Orgel
- Department of Pediatrics, UNC School of Medicine, Chapel Hill, North Carolina.,UNC Food Allergy Initiative, Chapel Hill, North Carolina
| | - Caitlin Burk
- Department of Pediatrics, UNC School of Medicine, Chapel Hill, North Carolina.,UNC Food Allergy Initiative, Chapel Hill, North Carolina
| | - Johanna Smeekens
- Department of Pediatrics, UNC School of Medicine, Chapel Hill, North Carolina.,UNC Food Allergy Initiative, Chapel Hill, North Carolina
| | - Jada Suber
- Department of Pediatrics, UNC School of Medicine, Chapel Hill, North Carolina.,UNC Food Allergy Initiative, Chapel Hill, North Carolina
| | - Lakeya Hardy
- Department of Pediatrics, UNC School of Medicine, Chapel Hill, North Carolina.,UNC Food Allergy Initiative, Chapel Hill, North Carolina
| | - Rishu Guo
- Department of Pediatrics, UNC School of Medicine, Chapel Hill, North Carolina.,UNC Food Allergy Initiative, Chapel Hill, North Carolina
| | - A Wesley Burks
- Department of Pediatrics, UNC School of Medicine, Chapel Hill, North Carolina.,UNC Food Allergy Initiative, Chapel Hill, North Carolina
| | - Michael Kulis
- Department of Pediatrics, UNC School of Medicine, Chapel Hill, North Carolina.,UNC Food Allergy Initiative, Chapel Hill, North Carolina
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