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Updated: Oct 23, 2025
Murine Model of Allergen Induced Asthma
Published on: May 14, 2012
Pollen shells and soluble factors play non-redundant roles in the development of allergic conjunctivitis in mice
Saaya Fukase1, Tomoaki Ando2, Moe Matsuzawa1
1Atopy (Allergy) Research Center, Juntendo University Graduate School of Medicine, Tokyo, 113-8421, Japan; Department of Ophthalmology, Juntendo University Urayasu Hospital, Urayasu, Chiba, 279-0021, Japan; Department of Ophthalmology, Juntendo University Graduate School of Medicine, Tokyo, 113-8421, Japan.
Purpose:
We aimed to clarify the role of particulate allergen exposure to the conjunctiva in the development of allergic conjunctivitis.
Methods:
We administered ragweed pollen suspension, pollen extract, pollen shell, particulate air pollutants, and their combinations to the mouse conjunctiva five days a week without prior sensitization. Clinical signs were scored. Histological changes, cellular infiltrations, mRNA expressions, lymph node cell recall responses, and serum immunoglobulin levels were assessed. Immune cell-depleting antibodies and ST2 knockout mice were used to investigate the cellular and molecular requirements.
Results:
Pollen suspension, but not the extract or shell alone, induced robust eosinophilic conjunctivitis, accompanied by a proliferative response of epithelial cells. A combination of pollen extract and shell completely restored eosinophil accumulation. In addition, eosinophilic conjunctivitis was induced by a mixture of particulate air pollutants and pollen extract. Mechanistically, eosinophil accumulation was ameliorated by deficiency of the IL-33 receptor ST2 and abolished by depleting CD4+ T cells. Pollen shells, but not the extract, induced IL-33 release from conjunctival epithelial cells in vivo.
Conclusions:
Our results indicate the non-redundant roles for the allergens' particulate properties and soluble factors in the development of allergic conjunctivitis.
Insights
Particulate allergens, like pollen shells, are crucial for developing allergic conjunctivitis. Their physical properties, alongside soluble factors, drive the immune response, highlighting key mechanisms in eye allergy development.
Area of Science:
- Ophthalmology
- Immunology
- Allergy Research
Background:
- Allergic conjunctivitis is a common ocular condition.
- The specific role of allergen particulate properties in conjunctival allergy is not fully understood.
Purpose of the Study:
- To investigate how particulate allergen exposure influences the development of allergic conjunctivitis.
- To elucidate the cellular and molecular mechanisms involved in allergen-induced conjunctival inflammation.
Main Methods:
- Mice were exposed to various forms of ragweed allergen (suspension, extract, shell) and particulate air pollutants.
- Evaluated clinical signs, histology, cellular infiltration, gene expression, and immune cell responses.
- Utilized ST2 knockout mice and immune cell depletion to identify key molecular and cellular players.
Main Results:
- Pollen suspension induced eosinophilic conjunctivitis; pollen shells and extract combined restored this effect.
- Particulate air pollutants combined with pollen extract also triggered conjunctivitis.
- Eosinophil accumulation was dependent on the IL-33 receptor ST2 and CD4+ T cells; pollen shells induced IL-33 release.
Conclusions:
- Both the physical form of allergens and soluble factors are essential for allergic conjunctivitis development.
- Particulate properties of allergens play a non-redundant role in initiating and sustaining conjunctival inflammation.
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