COMPARISON OF GENETIC SUSCEPTIBILITY TO EXPERIMENTAL ALLERGIC IMMUNE-MEDIATED BLEPHAROCONJUNCTIVITIS BETWEEN LEWIS AND FISCHER RATS/

Background: Fischer rats were less susceptible to experimental autoimm une uveoretinits (EAU) than Lewis rats, although both strains have the same MHC molecules. The purpose of this study was to compare the susc eptibility of experimental allergic/immune-mediated blepharoconjunctiv itis (EAC) between these two strains. Methods: Male Lewis and Fischer rats were immunized with either ovalbumin (OVA) or OVA peptide (OVA(32 3-339)) in complete Freund's adjuvant (CFA). Three weeks later, they w ere challenged with OVA by eye drops. Twenty-four hours later, after c linical evaluation, they were killed and eyes, blood and lymph nodes w ere harvested for histology, antibody titer and proliferation assay, c ytokine production or flow cytometric analysis, respectively. Results: Fischer rats developed mild EAC compared with Lewis rats. Cellular pr oliferative responses, IFN-gamma production of culture supernatant and serum IgG specific for OVA were basically the same between the two st rains. The same OVA peptides were selected as immunodominant. Flow cyt ometric analysis demonstrated the same cellular profile of lymph node cells in the two strains. Conclusion: EAC in Fischer rats was milder t han that in Lewis rats, although no apparent differences in immunologi cal parameters between these two strains were detected. These data sug gest that factors unrelated to immunological parameters may depend on the susceptibility of EAC.