Abstract
Purpose: :
We have previously shown that the pathogenic antigen – CI–α2 (22 kDa) purified from bovine iris and ciliary body causes severe EAAU in Lewis rats. The present study was undertaken to localize CI–α2 (22 kDa) within the rat eye and to further define the tissue specificity of this antigen.
Methods: :
Rabbit polyclonal and mouse monoclonal antibodies to bovine CIα2 (22kDa) were used to stain the eyes of normal Lewis rats. Brain, liver, kidney, spleen, lung and heart obtained from normal Lewis rats were used as control. Immunohistology was performed on paraffin–embedded tissue sections using both immunoperoxidase and immunofluorescence techniques. Control stains were performed without the primary and the secondary antibodies. The presence of CIα2 (22kDa) in rat intraocular fluid (AH and vitreous) was determined by Western blot analysis using both monoclonal and polyclonal antibodies raised against bovine CIα2 (22kDa).
Results: :
CIα2 (22kDa) was localized only to the iris and ciliary body with other ocular structures such as cornea, lens, choroid, RPE and retina did not stain. Additionally, CIα2 (22kDa) was not localized to the brain, liver, kidney, spleen, lung and heart demonstrating the organ–specificity of the antigen. CIα2 (22kDa) was detected as a soluble protein in normal rat AH but not rat vitreous.
Conclusions: :
Our results suggest that CI–α2 (22 kDa) is the auto–antigen associated with EAAU and resides within the iris and ciliary body of the Lewis rat eye.
Keywords: uveitis-clinical/animal model • autoimmune disease • uvea