Elucidation of Desensitization Mechanisms Induced by Oral Immunotherapy in a Rat Model of Ovalbumin Allergy

Oral immunotherapy (OIT) is a promising approach for treating food allergy. Here, we elucidated the mechanisms of desensitization induced by OIT in rats sensitized to ovalbumin (OVA). The desensitization was induced by ingestion of OVA three times per week after sensitization in rats. OIT suppressed...

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Main Authors: Daigo Takizawa, Tomoharu Yokooji, Chika Miyamoto, Yuki Koga, Keisuke Oda, Ryohei Ogino, Takanori Taogoshi, Hiroaki Matsuo
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/14/8/1424
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author Daigo Takizawa
Tomoharu Yokooji
Chika Miyamoto
Yuki Koga
Keisuke Oda
Ryohei Ogino
Takanori Taogoshi
Hiroaki Matsuo
author_facet Daigo Takizawa
Tomoharu Yokooji
Chika Miyamoto
Yuki Koga
Keisuke Oda
Ryohei Ogino
Takanori Taogoshi
Hiroaki Matsuo
author_sort Daigo Takizawa
collection DOAJ
description Oral immunotherapy (OIT) is a promising approach for treating food allergy. Here, we elucidated the mechanisms of desensitization induced by OIT in rats sensitized to ovalbumin (OVA). The desensitization was induced by ingestion of OVA three times per week after sensitization in rats. OIT suppressed the decrease in rectal temperature and increase in plasma histamine levels induced by OVA injection immediately and 4 weeks after OIT completion. Plasma OVA-specific IgE (sIgE) levels did not differ between the non-OIT and OIT groups, but OVA-specific IgG<sub>1</sub> levels were higher in the OIT group than in the non-OIT group at both timepoints. To evaluate IgG’s effect on IgE crosslinking with OVA, amplified luminescence proximity homogeneous assay involving crosslinking (AlphaCL) was performed. When IgG was removed using a Protein G column, the AlphaCL signal was significantly increased, especially in the OIT group, indicating that OIT-induced IgG inhibited the sIgE response. The proportions of cluster of differentiation (CD)4<sup>+</sup> cells and CD4<sup>+</sup>CD25<sup>+</sup>FoxP3<sup>+</sup> cells in mesenteric lymph nodes and spleen were similar between the two groups. These findings indicate that OIT attenuates systemic allergic responses by inhibiting sIgE binding to OVA through increased IgG. Our model is useful for understanding the mechanisms of OIT and optimizing therapeutic strategies for ameliorating food allergies.
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spelling doaj-art-deea446dcafc4e15a7c80b2c5f7741d62025-08-20T02:28:28ZengMDPI AGFoods2304-81582025-04-01148142410.3390/foods14081424Elucidation of Desensitization Mechanisms Induced by Oral Immunotherapy in a Rat Model of Ovalbumin AllergyDaigo Takizawa0Tomoharu Yokooji1Chika Miyamoto2Yuki Koga3Keisuke Oda4Ryohei Ogino5Takanori Taogoshi6Hiroaki Matsuo7Department of Pharmaceutical Services, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, JapanDepartment of Frontier Science for Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, JapanDepartment of Pharmaceutical Services, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, JapanDepartment of Pharmaceutical Services, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, JapanLaboratory of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmaceutical Sciences, Hiroshima International University, 5-1-1 Hirokoshingai, Kure, Hiroshima 737-0112, JapanDepartment of Frontier Science for Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, JapanDepartment of Pharmaceutical Services, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, JapanDepartment of Pharmaceutical Services, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, JapanOral immunotherapy (OIT) is a promising approach for treating food allergy. Here, we elucidated the mechanisms of desensitization induced by OIT in rats sensitized to ovalbumin (OVA). The desensitization was induced by ingestion of OVA three times per week after sensitization in rats. OIT suppressed the decrease in rectal temperature and increase in plasma histamine levels induced by OVA injection immediately and 4 weeks after OIT completion. Plasma OVA-specific IgE (sIgE) levels did not differ between the non-OIT and OIT groups, but OVA-specific IgG<sub>1</sub> levels were higher in the OIT group than in the non-OIT group at both timepoints. To evaluate IgG’s effect on IgE crosslinking with OVA, amplified luminescence proximity homogeneous assay involving crosslinking (AlphaCL) was performed. When IgG was removed using a Protein G column, the AlphaCL signal was significantly increased, especially in the OIT group, indicating that OIT-induced IgG inhibited the sIgE response. The proportions of cluster of differentiation (CD)4<sup>+</sup> cells and CD4<sup>+</sup>CD25<sup>+</sup>FoxP3<sup>+</sup> cells in mesenteric lymph nodes and spleen were similar between the two groups. These findings indicate that OIT attenuates systemic allergic responses by inhibiting sIgE binding to OVA through increased IgG. Our model is useful for understanding the mechanisms of OIT and optimizing therapeutic strategies for ameliorating food allergies.https://www.mdpi.com/2304-8158/14/8/1424food allergyovalbuminoral immunotherapyallergen-specific IgEallergen-specific IgG
spellingShingle Daigo Takizawa
Tomoharu Yokooji
Chika Miyamoto
Yuki Koga
Keisuke Oda
Ryohei Ogino
Takanori Taogoshi
Hiroaki Matsuo
Elucidation of Desensitization Mechanisms Induced by Oral Immunotherapy in a Rat Model of Ovalbumin Allergy
Foods
food allergy
ovalbumin
oral immunotherapy
allergen-specific IgE
allergen-specific IgG
title Elucidation of Desensitization Mechanisms Induced by Oral Immunotherapy in a Rat Model of Ovalbumin Allergy
title_full Elucidation of Desensitization Mechanisms Induced by Oral Immunotherapy in a Rat Model of Ovalbumin Allergy
title_fullStr Elucidation of Desensitization Mechanisms Induced by Oral Immunotherapy in a Rat Model of Ovalbumin Allergy
title_full_unstemmed Elucidation of Desensitization Mechanisms Induced by Oral Immunotherapy in a Rat Model of Ovalbumin Allergy
title_short Elucidation of Desensitization Mechanisms Induced by Oral Immunotherapy in a Rat Model of Ovalbumin Allergy
title_sort elucidation of desensitization mechanisms induced by oral immunotherapy in a rat model of ovalbumin allergy
topic food allergy
ovalbumin
oral immunotherapy
allergen-specific IgE
allergen-specific IgG
url https://www.mdpi.com/2304-8158/14/8/1424
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