Abstract
Abstract: :
Purpose:A monoclonal pANCA antibody, Fab 5-3, defines certain ciliary body proteins that are potential antigenic targets in human uveitis (Clin. Immunol. 94:42, 2000). One prominent ciliary body-associated pANCA antigens was identified as beta B1 crystallin, a surprising result as expression of this protein outside of the lens is not completely characterized. The goal of this study was to evaluate the expression of beta B1 crystallin in ocular structures. Methods:Microdissected human ocular tissue was evaluated for the expression of beta B1 crystallin. Samples of cornea, lens, ciliary body, retina, retinal pigment epithelium, sclera, and optic nerve were evaluated by several methods for expression of beta B1 crystallin. Protein expression was evaluated in tissue extracts by Western immunoblotting using an anti-peptide antibody against a beta B1 crystallin specific sequence. RT-PCR was performed on RNA extracted from microdissected tissues and on samples obtained through laser capture microdissection of snap-frozen ocular samples. Northen blot confirmation of the RNA was also performed on selected ocular tissues. Results:Beta B1 crystallin protein was specifically identified by Western immunoblotting in cellular extracts of the lens and ciliary body. Confirmation of expression in these two ocular sites was performed by both RT-PCR and Northern blot. No other ocular structure demonstrated expression of Beta B1 crystallin by these methods. Conclusion:In the eye, Beta B1 crystallin is expressed in the lens and ciliary body. Further study is merited on the role of this protein in the cell biology of the ciliary body and its expression in non-ocular tissues. The significance of this protein in anterior uveitis is currently under evaluation, but there is evidence for widespread immunoreactivity in anterior uveitis against Beta B1 crystallin. The expression in the cililary body, a site of initial inflammation in uveitis, is intriguing and suggests a possible role in uveitis immunopathogenesis.
Keywords: 612 uveitis-clinical/animal model • 378 crystallins • 327 autoimmune disease