Immunosuppressive effect of cholera toxin B on allergic conjunctivitis model in the guinea Pig.

Purpose: To investigate the immunosuppressive effects of mucosal immune therapy in experimental allergic conjunctivitis.Method: We used 11 white Hartrey guinea pigs divided into two groups. Six animals (treated group) received pretreatment with topical instillation of cholera toxin B (4 &mgr;g/30 ml) and ovalbumin (10 &mgr;g/30 ml). The other group of 5 animals served as control. All the animals received intra-abdominal injection of ovalbumin (100 g/mL) and aluminum hydroxide (5 mg/mL) repeated twice 2 weeks apart. Allergic conjunctivitis was induced by topical instillation of ovalbumin solution (5 mg/mL) 1 week after the above procedure. Result: Both groups developed palpebral and bulbar edema with hyperemia 30 minutes after instillation. The allergic reaction was significantly less in score in the treated than in the control group (Mann-Whitney U-test: P <.01). The clinical findings subsided after 6 hours. The treated group showed less eosinophilic infiltration in the conjunctiva and the limbus, particularly in the conjunctival epithelium, than in the control group at 6 and 24 hours.Conclusion: Pretreatment with topical cholera toxin B and antigen suppresses clinical and histological findings in experimentally induced allergic conjunctivitis.