Development of Allergic Conjunctivitis Induced by House Dust Mite Extract From Dermatophagoides pteronyssinus.

PURPOSE: The purpose of this study was to develop a murine model of allergic conjunctivitis induced by house dust mite (HDM) extract from Dermatophagoides pteronyssinus, a major allergen in humans.

METHODS

Forty BALB/c mice were divided into five groups, immunized with placebo, ovalbumin (10 μg), or HDM extract following a schedule. Twenty minutes after topical challenge, mice were examined clinically. Material collected from mice was used for measuring total and specific IgE, antigen-specific lymphocyte proliferation, and supernatant cytokine levels and for conjunctival histopathology and flow cytometric analysis of conjunctival cells.

RESULTS

This murine model showed similar clinical signs and laboratory findings to human allergy and the ovalbumin-induced allergic conjunctivitis model. Total IgE levels and conjunctival infiltration of mast cells and eosinophils in immunized mice were significantly higher than in the control group. Cervical lymphocyte proliferation was increased in antigen-stimulated cultures in immunized mice, concomitant with significantly higher IL-4 and IL-5 levels in the culture supernatant. The proportion of conjunctival CD4+ T cells expressing the ST2 receptor was increased, and conjunctival CD4+ST2+ T cells exhibited an increase in intracellular IL-5.

CONCLUSIONS

House dust mite extract successfully induced allergic conjunctivitis in BALB/c mice. Ten micrograms of HDM extract was the optimal dose for systemic immunization in this model. This murine model is suitable for further studies on HDM-induced allergic conjunctivitis, and the data show that conjunctival CD4+ T cells expressing ST2 may play an important role in IL-5 secretion, recruiting eosinophils into conjunctiva on ocular allergen challenge.