Genetic background determines the nature of immune responses and experimental immune-mediated blepharoconjunctivitis (EC)

Purpose. Experimental immune-mediated blepharoconjunctivitis (EC) was induc ed in Lewis rats by immunization with ovalbumin (OVA) in complete Freund's adjuvant (CFA) or aluminum hydroxide [AI(OH)(3)]. To investigate the affect of genetic factors on the susceptibility of EC, we tested different strain s of rats for the development of EC. Methods. Lewis and Brown Norway (BN) rats were immunized once with 100 mu g of OVA in CFA or Al(OH)(3). Three weeks later they were challenged with OV A in eye drops; 24 hours after the challenge they were sacrificed and their eyes, blood, and lymph nodes were harvested for histological studies, meas urement of OVA-specific antibodies (Igc, IgG 1, IgG2a, IgE), and proliferat ion or cytokine assay, respectively. ELISA was used to detect OVA-specific IgG; passive cutaneous anaphylaxis was used for detecting IgE. Results. EC, OVA-specific IgG, and cellular immunity were induced in Lewis rats by using either adjuvant, whereas IgE was not produced by either adjuv ant. In contrast, IgE was produced in BN rats using either adjuvant, wherea s cellular immunity was evoked only when CFA was used. Less cellular infilt ration as well as cellular proliferation was detected in BN rats immunized with Al(OH)(3). In both strains, Al(OH)(3) induced a higher IgG1/IgG2a rati o than did CFA. More interferon-gamma by stimulation with OVA was noted in Lewis rats compared to BN rats, whereas interleukin-4 was detected only in BN rats. Conclusions. The severity of EC evaluated by cellular infiltration was depe ndent on OVA-specific cellular immunity. Genetic background is more importa nt than adjuvants in determining the nature of EC and immunity.