Search

Unlabelled: PURPOSE. The occurrence of eye diseases of autoimmune nature, as well as experimental models of these diseases, has been attributed to the sequestration of ocular antigens from the immune system, that prevents the development of tolerance against these antigens. Here, we tested this assertion by examining whether transcripts of certain ocular antigens are constitutively expressed in the thymus, the site of central tolerance induction., Method: RNA was isolated from the eyes and thymi of two mouse strains and analyzed for the expression of genes encoding four retinal and three lens proteins by reverse transcribed-polymerase chain reaction. Southern blot and DNA sequence analyses., Results: We detected gene transcripts of S-Antigen (S-Ag), interphotoreceptor retinoid-binding protein, opsin, recoverin, lens major intrinsic protein (MIP), alphaA-, alphaA(-ins)- and gamma-crystallins in the thymi of BALB/c and FVB/N mouse strains. DNA sequence analysis of the thymic MIP and S-Ag transcripts confirmed their identity to the lens and retinal proteins, respectively., Conclusions: Our results reveal that transcripts of several ocular-specific proteins are expressed in the thymus and suggest that the commonly held view that ocular-specific antigens are sequestered from the immune system should be modified.

Experimental autoimmune uveoretinitis (EAU) is a T cell mediated autoimmune disease that serves as a model of human intraocular inflammatory disease (uveitis). It is initiated in susceptible animals by immunization with retinal antigens, such as interphotoreceptor retinoid binding protein (IRBP) and S-Antigen (SAg) or by adoptive transfer of ocular Ag-specific uveitogenic T cells. Previous studies of T cell receptor (TCR) usage by uveitogenic T cells have implicated Vβ8(+) -expressing T cells in the pathogenesis of EAU. Here, the authors have analyzed the TCR Vγ repertoire in the retinas of Lewis rats with and without EAU as well as the repertoire of several SAg- or IRBP-specific T cell lines. They detected Vγ2 transcripts in all four pathogenic lines and in the retinas of Lewis rats with EAU but not in the two non-pathogenic lines nor in the retinas of naive rats. Vγ7 transcripts were detected in RNAs obtained from the retina, regardless of whether the rat had EAU or not. However, the authors could not detect Vγ4, Vγ5 or Vγ6 TCR transcripts in any of the samples analyzed. Taken together, their data suggests a correlation between recruitment of Vγ2(+) T cells and EAU pathogenesis.