Complement in Experimental Autoimmune Anterior Uveitis

Abstract

Purpose: : To study complement activation (both local and systemic) and the levels of complement regulatory proteins (CRPs) during experimental autoimmune anterior uveitis (EAAU).

Methods: : EAAU was induced in Lewis rats by immunization with bovine melanin associated antigen (MAA). Rats were sacrificed (n=6/time point) at day 8, 10, 12, 14, 16, 19, 23 and 30 post–immunization. Serum complement levels were monitored using CH50 hemolytic assay and complement activation within the eye was monitored by semi–quantitative Western blot for iC3b. CD59 and Crry levels were monitored by quantitative RT–PCR and semi–quantitative Western blot.

Results: : A strong correlation between serum complement activity and the clinical course of EAAU was observed. In addition, levels of iC3b within the eye paralled the course of disease in EAAU. Constitutive expression of Crry and CD59 (protein and mRNA) was observed in the eyes of naïve Lewis rats. However, the expression of both Crry and CD59 was up–regulated during EAAU. CD59 and Crry mRNA and protein increased at the onset of the disease and remained elevated even after the resolution of intraocular inflammation.

Conclusions: : Our results suggest that local and systemic complement activation plays an important role in EAAU. These results further suggest that various ocular tissues up–regulate the expression of Crry and CD59 to avoid self–injury during autoimmune uveitis.

Keywords: autoimmune disease • inflammation • uveitis-clinical/animal model