Incidence Of Experimental Autoimmune Uveoretinitis Research Articles

Local Activation of Dendritic Cells Alters the Pathogenesis of Autoimmune Disease in the Retina

Interest in the identities, properties, functions, and origins of local APC in CNS tissues is growing. We recently reported that dendritic cells (DC) distinct from microglia were present in quiescent retina and rapidly responded to injured neurons. In this study, the disease-promoting and regulatory contributions of these APC in experimental autoimmune uveoretinitis (EAU) were examined. Local delivery of purified, exogenous DC or monocytes from bone marrow substantially increased the incidence and severity of EAU induced by adoptive transfer of activated, autoreactive CD4 or CD8 T cells that was limited to the manipulated eye. In vitro assays of APC activity of DC from quiescent retina showed that they promoted generation of Foxp3(+) T cells and inhibited activation of naive T cells by splenic DC and Ag. Conversely, in vitro assays of DC purified from injured retina demonstrated an enhanced ability to activate T cells and reduced induction of Foxp3(+) T cells. These findings were supported by the observation that in situ activation of DC before adoptive transfer of β-galactosidase-specific T cells dramatically increased severity and incidence of EAU. Recruitment of T cells into retina by local delivery of Ag in vivo showed that quiescent retina promoted development of parenchymal Foxp3(+) T cells, but assays of preinjured retina did not. Together, these results demonstrated that local conditions in the retina determined APC function and affected the pathogenesis of EAU by both CD4 and CD8 T cells.

Mice lacking the IFN-γ receptor or fyn develop severe experimental autoimmune uveoretinitis characterized by different immune responses

Endogenous interferon (IFN)-gamma negatively regulates experimental autoimmune uveoretinitis (EAU), a Th1-mediated disease. Although it is well known that IFN-gamma exerts its effects by binding to the IFN-gamma receptor (IFN-gammaR), the role that IFN-gammaR plays in the development of EAU has not been investigated. Fyn has been reported to inhibit Th2 differentiation. We aimed to investigate how endogenous IFN-gammaR and fyn, which influence Th1/Th2 differentiation, participate in the development of EAU. Sex-matched 6- to 10-week-old C57BL/6 wild-type (WT), IFN-gammaR knockout (GRKO) and fyn knockout (fyn KO) mice were compared. Mice were immunized subcutaneously with human interphotoreceptor retinoid-binding protein peptide 1-20 emulsified in Freund's complete adjuvant together with an intraperitoneal injection of Bordetella pertussis toxin. Three weeks later, mice were sacrificed, and their eyes and spleens were harvested for histopathologic analyses and examination of cellular immune responses, respectively. Cellular immune responses were evaluated by measuring the proliferative responses and cytokine production [interleukin (IL)-4, IL-5, IL-6, IL-13, IFN-gamma and tumor necrosis factor (TNF)-alpha] of splenocytes. The incidence of EAU was 40.0% in WT mice, 59.3% in GRKO mice and 78.6% in fyn KO mice. The average EAU score was 0.294 in WT mice, 0.917 in GRKO mice and 1.063 in fyn KO mice. Upon EAU induction, significant infiltration of eosinophils into the eyes was observed in GRKO and fyn KO mice compared to WT mice. Splenocytes from GRKO mice proliferated against the antigen and a mitogen more vigorously than those from WT and fyn KO mice. Stimulation of splenocytes with the antigen induced a higher production of IL-4, IL-6, IL-13 and IFN-gamma in GRKO mice compared to WT and fyn KO mice. In contrast, IL-5 and TNF-alpha were most abundantly produced by splenocytes from fyn KO mice compared to WT and GRKO mice. The incidence and mean severity of EAU were significantly higher in GRKO and fyn KO mice than in WT mice, suggesting that endogenous IFN-gammaR and fyn negatively regulate the development of EAU. The different cytokine production patterns by the GRKO and fyn KO mice indicate that the negative regulatory mechanism mediated by IFN-gammaR and fyn may differ.

Suppression of Experimental Autoimmune Uveoretinitis With a Combination of Cyclosporin and Alloprinol

Purpose: We assessed the suppressive effect of a combination of cyclosporin (an immunosuppressive agent) and allopurinol (a xanthine oxidase inhibitor and radical scavenger) on experimental autoimmune uveoretinitis (EAU) in Lewis rats, induced by interphotoreceptor retinoid-binding protein (IRBP). Methods: After the immunization of Lewis rats with 30 μg of IRBP. We administrated cyclosporin and/or allopurinol to the IRBP-immunized Lewis rats. We observed the incidence and the severity of EAU. Histological, immunological, and biochemical examinations were performal 13 days after the immunization. The suppressive effect of these drugs in vitro on the production of free radicals derived from polymorphonuclear leukocytes. Results: The incidence of EAU was suppressed by 50% at 13 days after immunization, and in terms of clinical and histological findings, inflammatory reaction was more inhibited by the combination of these drugs than by either cyclosporin or allopurinol alone. Lymphocyte proliferation assay against IRBP was significantly inhibited by the combination of drugs. No adverse systemic effects were identified. Cyclosporin and allopurinol inhibited radical production both separately and in combination. Conclusion: This suggests that suppression of EAU is based not only on inhibited cell-mediated immunity but also on inhibited production of free radicals derived from polymorphonuclear leukocytes.

Prevention of experimental autoimmune uveoretinitis by intrathymic S-antigen injection

The objective of this paper was to determine whether intra-thymic injection of retinal S-antigen (S-Ag) can prevent experimental auto-immune uveoretinitis (EAU) in Lewis rats. Lewis rats were injected intra-thymically with 25-100 μg of S-Ag in 100 μ1 split between thymic lobes. Controls received vehicle alone (PBS) or 100 μg of BSA. Animals were im-munized two weeks later with 100 μg of S-Ag in CFA with or without per-tussis toxin (0.5 μg/rat). Clinical ocular disease was confirmed by histopa-thology. Splenocytes and lymph node cells were assayed, in vitro, for their ability to proliferate in response to various concentrations of S-Ag. Further-more, attempts were made to adoptively transfer protection to naive rats us-ing spleen cells from intrathymically injected animals and to adoptively transfer EAU to protected rats using Con A activated cells from affected animals. Intrathymic injection of S-Ag reduced the incidence of EAU in ani-mals subsequently immunized with S-Ag and pertussis, and prevented it en-tirely in rats immunized in the absence of pertussis. Splenic and lymph node cells from intrathymically injected animals showed reduced reactivity to S-Ag compared to controls, suggesting that intrathymic S-Ag injection may have rendered them tolerant to this antigen. We were unable to adoptively transfer protection to naive rats, nor were intrathymically injected rats pro-tected from EAU induced by the adoptive transfer of primed lymph node cells. These data demonstrate that intrathymic S-Ag injection can be an ef-fective method for protection from EAU, apparently through the induction of immunological tolerance and not active suppression. The tolerance was not absolute and could be overcome by increasing the intensity of the anti-genic challenge.

Immunological and immunopathological aspects of opsin-induced uveoretinitis.

In an extension of our previous studies, experimental autoimmune uveoretinitis (EAU) was induced in Lewis rats by injection of very high doses of bovine opsin. The induced reaction consisted predominantly of a mild posterior retinitis. Varying the amount of injected opsin between 300 and 1,000 micrograms did not influence this result, provided that the antigen was injected in Freund's complete adjuvant. Pathogenicity of opsin appeared to be lower than that of interphotoreceptor retinoid binding protein (IRBP) or S-antigen, while EAU induced by the latter antigens was much more dose-dependent than EAU induced by opsin. An increase of the dose strongly accelerated the onset and increased the incidence of EAU from low to moderate. However, severe inflammation and high incidence were only obtained by co-injection of Hemophilus pertussis bacteria. This adjuvant especially increased cellular immune responses to opsin as measured by lymphocyte transformation. No marked effects on humoral responses were detected by ELISA, using different types of opsin preparations. Development of opsin-induced EAU was inhibited by ciclosporin, a suppressor of certain specific T cell functions. Ciclosporin injections lowered the antibody response of the rats and eliminated measurable lymphocyte transformation in vitro. Induction of opsin-EAU therefore appears to be T-cell-dependent. The effect of pertussis adjuvant may be explained by enhancement of the T cell responses to opsin and by increasing the permeability of the blood-retina barriers. Other properties of the adjuvant may be of importance as well. A relationship between change in molecular conformation and uveitogenicity of opsin is discussed.