A novel oral immunotherapy strategy using transgenic barley induces Culicoides allergen-specific immune responses in horses.
Publisher DOI
PubMed ID
41743709
Abstract
Introduction
Insect bite hypersensitivity (IBH) is a seasonal, IgE-mediated allergic dermatitis of horses caused by salivary gland proteins of biting midges (Culicoides spp.). Current management relies on relief of clinical signs and on physical protection. In a previous pilot study, healthy horses were fed transgenic barley expressing a Culicoides allergen via a special spiral bit, which successfully induced allergen-specific antibody responses. Building on this concept, the present study aimed to evaluate a more practical feeding approach, delivering transgenic barley expressing the major Culicoides allergen Cul o 2p in a feed-compatible paste administered from buckets.
Methods
Twelve naïve Icelandic horses were randomized into treatment (n=6) and control (n=6) groups. The treatment group received 11.44 g of the major Culicoides allergen Cul o 2p/horse across three feeding phases. Serum and saliva were analyzed for Cul o 2p-specific antibodies (IgG1, IgG4/7, IgG5, IgA, IgE) by ELISA. IgE-blocking capacity was assessed in pooled serum, and cytokine responses (IL-10, IL-4, IFN-γ) measured after in vitro re-stimulation of peripheral blood mononuclear cells (PBMCs).
Results
Four of six treated horses produced Cul o 2p-specific IgG1, IgG4/7, and IgA in both serum and saliva. The induced antibodies could partly inhibit IgE binding. Elevated secretion of IFN-γ and IL-10 but no IL-4 secretion was observed in supernatants of re-stimulated PBMCs in treated horses compared to controls, reaching statistical significance for IFN-γ. No Cul o 2p-specific IgE was detected, and no adverse clinical reactions occurred during treatment.
Conclusion
The feed-based approach using transgenic barley paste induced Cul o 2p-specific humoral and cellular immune responses in naïve horses, supporting its potential as a scalable and field-feasible platform for prophylactic and therapeutic applications in IBH. Clinical trials in IBH-affected horses are warranted to assess efficacy.
Insect bite hypersensitivity (IBH) is a seasonal, IgE-mediated allergic dermatitis of horses caused by salivary gland proteins of biting midges (Culicoides spp.). Current management relies on relief of clinical signs and on physical protection. In a previous pilot study, healthy horses were fed transgenic barley expressing a Culicoides allergen via a special spiral bit, which successfully induced allergen-specific antibody responses. Building on this concept, the present study aimed to evaluate a more practical feeding approach, delivering transgenic barley expressing the major Culicoides allergen Cul o 2p in a feed-compatible paste administered from buckets.
Methods
Twelve naïve Icelandic horses were randomized into treatment (n=6) and control (n=6) groups. The treatment group received 11.44 g of the major Culicoides allergen Cul o 2p/horse across three feeding phases. Serum and saliva were analyzed for Cul o 2p-specific antibodies (IgG1, IgG4/7, IgG5, IgA, IgE) by ELISA. IgE-blocking capacity was assessed in pooled serum, and cytokine responses (IL-10, IL-4, IFN-γ) measured after in vitro re-stimulation of peripheral blood mononuclear cells (PBMCs).
Results
Four of six treated horses produced Cul o 2p-specific IgG1, IgG4/7, and IgA in both serum and saliva. The induced antibodies could partly inhibit IgE binding. Elevated secretion of IFN-γ and IL-10 but no IL-4 secretion was observed in supernatants of re-stimulated PBMCs in treated horses compared to controls, reaching statistical significance for IFN-γ. No Cul o 2p-specific IgE was detected, and no adverse clinical reactions occurred during treatment.
Conclusion
The feed-based approach using transgenic barley paste induced Cul o 2p-specific humoral and cellular immune responses in naïve horses, supporting its potential as a scalable and field-feasible platform for prophylactic and therapeutic applications in IBH. Clinical trials in IBH-affected horses are warranted to assess efficacy.
Date Issued
2026
Publication Type
Article
Subject(s)
Subjects
Culicoides midges
•
allergy
•
horse (Equus caballus)
•
insect bite hypersensitivity
•
oral immunotherapy (OIT)
•
transgenic barley
Language(s)
en
Author(s)
Stefansdottir, Sara Björk | |
Torsteinsdottir, Sigurbjörg | |
Svansson, Vilhjalmur | |
Björnsson, Jon Mar | |
Wagner, Bettina | |
Journal
Frontiers in Immunology
Publisher
Frontiers Media
ISSN
1664-3224
Access(Rights)
open.access