Comparison of genetic susceptibility to experimental allergic/immune-mediated blepharoconjunctivitis between Lewis and Fischer rats.

Background: Fischer rats were less susceptible to experimental autoimmune uveoretinitis (EAU) than Lewis rats, although both strains have the same MHC molecules. The purpose of this study was to compare the susceptibility of experimental allergic/immune-mediated blepharoconjunctivitis (EAC) between these two strains.
Methods: Male Lewis and Fischer rats were immunized with either ovalbumin (OVA) or OVA peptide (OVA323-339) in complete Freund's adjuvant (CFA). Three weeks later, they were challenged with OVA by eye drops. Twenty-four hours later, after clinical evaluation, they were killed and eyes, blood and lymph nodes were harvested for histology, antibody titer and proliferation assay, cytokine production or flow cytometric analysis, respectively.
Results: Fischer rats developed mild EAC compared with Lewis rats. Cellular proliferative responses, IFN-gamma production of culture supernatant and serum IgG specific for OVA were basically the same between the two strains. The same OVA peptides were selected as immunodominant. Flow cytometric analysis demonstrated the same cellular profile of lymph node cells in the two strains.
Conclusion: EAC in Fischer rats was milder than that in Lewis rats, although no apparent differences in immunological parameters between these two strains were detected. These data suggest that factors unrelated to immunological parameters may depend on the susceptibility of EAC.