Inducing ocular allergy with beta-lactoglobulin: a new experimental model.

PURPOSE:To develop a new experimental ocular allergy animal model induced by beta-lactoglobulin (BLG), a major cow's milk allergen, and to discuss the clinical, histopathological and immunohistochemical findings. METHODS:Forty Balb/c mice were randomized and separated into groups of 10. Groups were determined according to the different concentrations of BLG drops used. Study groups were immunized with 2.5, 5 or 10 mg/ml topical BLG (groups 2, 3 and 4, respectively) following intraperitoneal injection for the systemic immunization. The control group (group 1) was immunized with aluminium hydroxide (alum) alone within the same intervals. After ocular challenge, all the animals were evaluated clinically, histopathologically (mast cell and eosinophil infiltration) and immunhistochemically in terms of both T helper type 1- (IFNgamma, TNFalpha) and T helper type 2- (IL-3, IL-4, IL-5, IL-10) specific cytokines. RESULTS:Both clinical and immunohistochemical findings showed that an allergic conjunctivitis was induced in all study groups, with an optimized dosage of topical 5 mg/ml BLG. The conjunctivitis was associated with both Th1 and Th2 response, with a slight predominance of Th1 reaction. CONCLUSION:We describe a new murine model of acute allergic conjunctivitis induced by BLG. We believe that this new preliminary model has the immune parameters of the late phase of acute allergic conjunctivitis and it provides an alternative means for studying the pathogenesis and future treatments of ocular allergy. Our results should be enhanced with more detailed cellular and humoral parameters.