Induction of experimental autoimmune uveoretinitis in Lewis rats with purified recombinant human retinal S-antigen fusion protein

Prevalence and clinical impact of antiretinal antibodies in uveitis

PURPOSE

To determine the prevalence of serum antiretinal antibodies (ARAs) among patients with uveitis and establish their clinical relevance.

METHODS

This prospective study assessed the presence of ARAs by indirect immunofluorescence (IIF) using primate retina in 126 patients with uveitis and 60 healthy controls. Clinical data of uveitis patients were collected from medical charts and included the classification of uveitis, cause of uveitis or its association with systemic disease, stage and activity of uveitis and specific retinal features. Correlations between the presence of specific ARAs and various clinical characteristics were analysed.

RESULTS

The presence of ARAs was observed in 49 of 104 (47%) of patients with uveitis and in 10 of 59 (17%) of healthy controls (p < 0.001). Staining of the nuclear layers or the photoreceptors were both more often observed in patients with uveitis compared to healthy controls (p = 0.002 and p = 0.018, respectively). No specific associations were found between the presence of serum ARAs and various clinical characteristics.

CONCLUSION

Serum ARAs were more frequent in patients with uveitis compared to healthy controls, but their clinical role remains elusive. The assessment of intraocular production of specific ARAs may provide further insight into the role of ocular autoantibodies in diverse uveitis entities.

Chronic recurrent autoimmune uveitis with progressive photoreceptor damage induced in rats by transfer of IRBP-specific T cells

Recurrent uveitis is a common cause of vision blindness. Using a rat model of chronic recurrent uveitis, we examined the relationship between clinical expression, pathological changes, and the heterogeneity of the disease. Chronic recurrent uveitis was induced by adoptive transfer of interphotoreceptor retinoid-binding protein (IRBP)-specific T cells in a total of more than 60 Lewis rats. In about 75% of cases recurrent uveitis was pathologically a chronic and progressive disease. The major pathological changes included the gradual loss of photoreceptor cells. However, disease progression did not always parallel the severity of ocular inflammation and clinical recurrent disease, with about a quarter showing no pathological damage in the eye.

Expression of autoimmune disease-related antigens by cells of the immune system

The process of thymic selection is critical for the generation of the mature T-cell repertoire, yet the nature of the self-peptides that serve this function is not known. Several studies suggest that tissue-specific auto-antigens are expressed in the thymus. We initiated this study to examine the expression of a panel of auto-antigens related to several autoimmune diseases in the thymus, peripheral lymphoid organs, and various cell lines. We looked for the expression of these antigens by reverse transcriptase-polymerase chain reaction, fluorescence-activated cell sorter (FACS) analysis, immunoblotting, and immunoprecipitation. We found that in the thymus there is evidence for the expression of a wide variety of disease-related self-antigens including myelin antigens, insulin, cardiac myosin, and retinal S antigen. By FACS analysis, several monoclonal anti-myelin basic protein antibodies were found to bind to immune cells. In Western blotting, we could find in the thymus and other lymphoid organs the expression of myelin basic protein, proteolipid protein, and cyclic nucleotide phosphodiesterase; in contrast, the staining for myelin oligodendrocyte glycoprotein, microtubule-associated Tau protein, and insulin were negative in these organs. The results of these studies confirm that there is evidence for the expression of a variety of auto-antigens in the immune system, both at the mRNA and protein levels, potentially enabling them to participate in the process of thymic education.

Antigen-specific T cell recognition of affinity-purified and recombinant thyroid peroxidase in autoimmune thyroid disease

The T cell proliferative responses of peripheral blood lymphocytes from 20 patients with autoimmune thyroid disease (AITD) and 20 healthy controls were analysed to immunoaffinity-purified thyroid peroxidase (TPO) and recombinant antigen preparations generated in Escherichia coli as glutathione-s-transferase fusion proteins. The epitope specificity of the T cell response was investigated using a selection of eight discrete recombinant fragments encompassing the whole of the extracellular region of the TPO molecule. Significant differences in the proliferative responses between patients and controls were observed to the full length, affinity-purified TPO molecule (P less than 0.002) as well as to the recombinant fragments R1c (residues 145-250) (P less than 0.001) and R2b (residues 457-589) (P less than 0.001) suggesting the presence of at least two distinct T cell determinants on this autoantigen. One of these T cell epitopes, localized within the region R1c, has not previously been identified by studies with synthetic peptides.