Ocular allergy modulation to hi-dose antigen sensitization is a Treg-dependent process

Area of Science:

• Immunology
• Allergy Research
• Cellular Immunology

Background:

• High-dose antigen (Ag) sensitization via intraperitoneal (IP) injection can inhibit allergic immune responses.
• The specific role of CD4+ CD25+ FoxP3+ T regulatory cells (Treg) in this inhibition, particularly in ocular allergy, remains largely uncharacterized.

Purpose of the Study:

• To investigate whether high-dose sensitization modulates ocular allergy.
• To determine the involvement of CD4+ CD25+ FoxP3+ Treg in this allergy modulation process.

Main Methods:

• C57BL/6 mice were sensitized with low-dose (100 µg) or high-dose (1000 µg) ovalbumin (OVA) with adjuvants.
• Treg cells were depleted using anti-CD25 antibody (PC61) or adoptively transferred from high-dose sensitized mice.
• Clinical signs, IgE levels, T cell cytokines (including TGF-β), and eosinophil recruitment were assessed following OVA challenge.

Main Results:

• High-dose sensitization, unlike low-dose, significantly reduced clinical allergy signs, serum IgE, Th2 responses, and eosinophil infiltration.
• T cells from high-dose sensitized mice exhibited increased TGF-β production, and their Treg cells suppressed effector T cell proliferation in vitro.
• In vivo Treg depletion reversed the allergy modulation in high-dose sensitized mice.
• Adoptive transfer of Treg from high-dose sensitized mice conferred allergy modulation to low-dose sensitized recipients.

Conclusions:

• High-dose antigen sensitization modulates allergic responses, including ocular allergy, in a T regulatory cell-dependent manner.
• These findings highlight the critical role of Treg cells in high-dose Ag-induced tolerance and suggest a potential therapeutic strategy for allergic diseases.