Purpose: To investigate the new method of immunotherapy using cholera toxin B (CTB) in experimental allergic conjunctivitis.
Methods: We used 21 white Hartley guinea pigs. The animals were sensitized by intraperitoneal injection of ovalbumin (100 microg/mL) and albumin hydroxide (5 mg/mL) repeated after an interval of 2 weeks. One week after the second injection, conjunctivitis was induced by topical instillation of ovalbumin (5 mg/mL). The animals were divided into two groups, CTB group and control group. The CTB group underwent pretreatment of topical instillation of CTB (4 microg/30 mL) and ovalbumin (10 microg/30 mL), three times a day for 3 days, 1 week before the intraperitoneal injection. The control group did not undergo the pretreatment. Clinical examination was performed at 0.5, 6, and 24 hours after the development of conjunctivitis. Histological examination was performed at 6 and 24 hours.
Results: Both groups developed palpebral and bulbar edema with hyperemia 30 minutes after instillation of ovalbumin. The allergic reaction score was significantly less in the CTB group than in the control group (Mann-Whitney U-test: P <.01). The clinical reactions subsided after 6 hours. The CTB group showed less eosinophilic infiltration in the conjunctiva and the limbus, particularly in the conjunctival epithelium, than the control group at 6 and 24 hours.
Conclusion: Pretreatment with topical CTB and antigen suppresses clinical and histological findings in experimentally induced allergic conjunctivitis.