Treatment Of Experimental Autoimmune Uveitis Research Articles

Biopotency and surrogate assays to validate the immunomodulatory potency of extracellular vesicles derived from mesenchymal stem/stromal cells for the treatment of experimental autoimmune uveitis.

Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have been recognized as promising cytotherapeutics due to their demonstrated immunomodulatory effects in various preclinical models. The immunomodulatory capabilities of EVs stem from the proteins and genetic materials they carry from parent cells, but the cargo contents of EVs are significantly influenced by MSC tissues and donors, cellular age and culture conditions, resulting in functional variations. However, there are no surrogate assays available to validate the immunomodulatory potency of MSC-EVs before in vivo administration. In previous work, we discovered that microcarrier culture conditions enhance the immunomodulatory function of MSC-EVs, as well as the levels of immunosuppressive molecules such as TGF-β1 and let-7b in MSC-EVs. Building on these findings, we investigated whether TGF-β1 levels in MSC-EVs could serve as a surrogate biomarker for predicting their potency in vivo. Our studies revealed a strong correlation between TGF-β1 and let-7b levels in MSC-EVs, as well as their capacity to suppress IFN-γ secretion in stimulated splenocytes, establishing biopotency and surrogate assays for MSC-EVs. Subsequently, we validated MSC-EVs generated from monolayer cultures (ML-EVs) or microcarrier cultures (MC-EVs) using murine models of experimental autoimmune uveoretinitis (EAU) and additional in vitro assays reflecting the Mode of Action of MSC-EVs invivo. Our findings demonstrated that MC-EVs carrying high levels of TGF-β1 exhibited greater efficacy than ML-EVs in halting disease progression in mice with EAU as well as inducing apoptosis and inhibiting the chemotaxis of retina-reactive T cells. Additionally, MSC-EVs suppressed the MAPK/ERK pathway in activated T cells, with treatment using TGF-β1 or let-7b showing similar effects on the MAPK/ERK pathway. Collectively, our data suggest that MSC-EVs directly inhibit the infiltration of retina-reactive T cells toward the eyes, thereby halting the disease progression in EAU mice, and their immunomodulatory potency in vivo can be predicted by their TGF-β1 levels.

Polyvinylpyrrolidone-curcumin nanoparticles with immune regulatory and metabolism regulatory effects for the treatment of experimental autoimmune uveitis

Uveitis comprises a cluster of intraocular inflammatory disorders characterized by uncontrolled autoimmune responses and excessive oxidative stress leading to vision loss worldwide. In the present study, curcumin (CUR) was conjugated with polyvinylpyrrolidone (PVP) to form PVP-CUR nanoparticles with significantly elevated solubility and outstanding multiple radical scavenging abilities. In vitro studies revealed that PVP-CUR nanoparticles markedly mitigated oxidative stress and reduced apoptosis in a H2O2-induced human retinal pigment epithelial cell line (ARPE-19) and promoted phenotypic polarization from M1 to M2 in an LPS-induced human microglial cell line (HMC3). Further in vivo studies demonstrated the prominent therapeutic effects of PVP-CUR nanoparticles on experimental autoimmune uveitis (EAU), which relieved clinical and pathological progression, improved perfusion and tomographic manifestations of retinal vessels, and reduced blood–retinal barrier (BRB) leakage; these effects may be mediated by mitigating oxidative stress and attenuating macrophage/microglia-elicited inflammation. Notably, treatment with PVP-CUR nanoparticles was shown to regulate metabolite alterations in EAU rats, providing novel insights into the underlying mechanisms involved. Additionally, the PVP-CUR nanoparticles showed great biocompatibility in vivo. In summary, our study revealed that PVP-CUR nanoparticles may serve as effective and safe nanodrugs for treating uveitis and other oxidative stress- and inflammation-related diseases.

Small extracellular vesicle-based delivery of interleukin-10 improves treatment of experimental autoimmune uveitis

Non-infectious uveitis is an intraocular autoimmune disease mainly characterized by immune dysregulation of the eye, which may cause blindness if not well treated. Interleukin 10 (IL-10) is a potent cytokine with multiple immunoregulatory functions. However, it's in vivo activity is unstable owing to its inherent protein instability and short plasma half-life. Therefore, our previous research tried to establish IL-10-overexpressing MSC-sEVs (sEVs-IL10) using lentiviral transfection. While this approach indeed improved drug delivery, it also suffered from tedious procedures and limited loading efficiency. Accordingly, we constructed a novel MSC-sEVs-based delivery system for IL-10 (IL-10@sEVs) by sonication. The obtained formulation (IL-10@sEVs) had relatively higher loading efficiency and exerted a more profound immunomodulatory effect than sEVs-IL10 in vitro. Furthermore, IL-10@sEVs had significant therapeutic effects in a mouse model of experimental autoimmune uveitis (EAU) by decreasing the percentage of Th17 cells, increasing regulatory T cells in the eye, and draining lymph nodes. In summary, sonication outperforms conventional transfection methods for loading IL-10 into MSC-sEVs.

Phasic regulation of the ATP/P2X7 receptor signaling pathway affects the function of antigen-presenting cells in experimental autoimmune uveitis.

Purinergic ligand-gated ion channel 7 receptor (P2X7R) is a purine type P2 receptor that is expressed on a variety of immune cells. Recent studies have shown that P2X7R signaling is required to trigger an immune response, and P2X7R antagonist-oxidized ATP (oxATP) effectively blocks P2X7R activation. In this study, we investigated the effect of phasic regulation of the ATP/P2X7R signaling pathway on antigen-presenting cells (APCs) by constructing an experimental autoimmune uveitis (EAU) disease model. Our results demonstrated that APCs isolated from the 1st, 4th, 7th and 11th days of EAU presented antigen function and could stimulate the differentiation of naive T cells. Moreover, after stimulation by ATP and BzATP (a P2X7R agonist), antigen presentation, promoting differentiation and inflammation were enhanced. The regulation of the Th17 cell response was significantly stronger than that of the Th1 cell response. In addition, we verified that oxATP blocked the P2X7R signaling pathway on APCs, attenuated the effect of BzATP, and significantly improved the adoptive transfer EAU induced by antigen-specific T cells cocultured with APCs. Our results demonstrated that at an early stage of EAU, the ATP/P2X7R signaling pathway regulation of APCs was time dependent, and the treatment of EAU could be achieved by intervening in P2X7R function on APCs.

Pharmacodynamic mechanism of Tibetan medicine Liurui Capsules on experimental autoimmune uveitis in rats based on network pharmacology and animal experiments

By integrating network pharmacology and animal experiments, we studied the pharmacodynamic mechanism of the Tibetan medicine Liurui Capsules in the treatment of experimental autoimmune uveitis(EAU). The active ingredients and targets of Liurui Capsules were searched against the Encyclopedia of Traditional Chinese Medicine(ETCM), Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicine(BATMAN-TCM), and relevant literatures. The EAU-related targets were obtained from Gene Expression Omnibus(GEO), GeneCards, Online Mendelian Inheritance in Man(OMIM), and Therapeutic Target Database(TTD). The common targets shared by Liurui Capsules and EAU were identified, and the protein-protein interaction(PPI) network was established via STRING. Gene Ontology(GO) annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis were conducted via g: Profiler. The rat model of EAU was induced by interphotoreceptor retinoid-binding protein(IRBP) and treated with Liurui Capsules. The inflammatory response of anterior segment and the pathological morphology of retina were observed. The mRNA and protein levels of delta-like ligand 4(DLL4), Notch1, interleukin-17(IL-17), and tumor necrosis factor-alpha(TNF-α) were determined by real-time quantitative PCR(q-PCR) and Western blot, respectively. The network pharmacology analysis predicted 51 common targets of Liurui Capsules and EAU, which were mainly involved in IL-17, TNF, and nuclear factor-kappa B(NF-κB) signaling pathways, as well as liposome receptors and other biological processes. Compared with the control group, the modeling of EAU caused inflammatory changes in the anterior segment and retina and up-regulated mRNA and protein levels of DLL4, Notch1, IL-17, and TNF-α in ocular tissue. Compared with the model group, Liurui Capsules reduced the inflammatory reaction of anterior segment and retina and down-regulated the mRNA and protein levels of DLL4, Notch1, IL-17, and TNF-α. Liurui Capsules can down-regulate the expression of the proteins involved in DLL4/Notch1/IL-17 signaling pathway in ocular tissue and alleviate the ocular inflammation, which may be one of the mechanisms of Liurui Capsules in the treatment of EAU.

Timing Effect of Adenosine-Directed Immunomodulation on Mouse Experimental Autoimmune Uveitis.

Adenosine is an important regulatory molecule of the immune response. We have previously reported that treatment of experimental autoimmune uveitis (EAU)-prone mice with an adenosine-degrading enzyme (adenosine deaminase) prohibited EAU development by inhibiting Th17 pathogenic T cell responses. To further validate that the targeting of adenosine or adenosine receptors effectively modulates Th17 responses, we investigated the effect of adenosine receptor antagonists. In this study, we show that the A2AR antagonist SCH 58261 (SCH) effectively modulates aberrant Th17 responses in induced EAU. However, timing of the treatment is important. Whereas SCH inhibits EAU when administered during the active disease stage, it did not do so if administered during quiescent disease stages, thus implying that the existing immune status influences the therapeutic effect. Mechanistic studies showed that inhibition of γδ T cell activation is crucially involved in adenosine-based treatment. Adenosine is an important costimulator of γδ T cell activation, which is essential for promoting Th17 responses. During ongoing disease stages, adenosine synergizes with existing high levels of cytokines, leading to augmented γδ T cell activation and Th17 responses, but in quiescent disease stages, when existing cytokine levels are low, adenosine does not enhance γδ T cell activation. Our results demonstrated that blockade of the synergistic effect between adenosine and inflammatory cytokines at active disease stages can ameliorate high-degree γδ T cell activation and, thus, suppress Th17 pathogenic T cell responses.

Preliminary study on prevention and treatment of experimental autoimmune uveitis by blocking CD73 detachment from the surface of retinal pigment epithelial cells with matrix metalloprotein-9 inhibitor

Objective To preliminarily investigate the mechanism of MMP-9 blocking CD73 detachment from RPE cells surface and preventing and treating experimental autoimmune pigment membranitis(EAU). Methods RPE cells isolated from wild-type C57BL/6 and CD73 gene knockout (CD73-/-) mice were cultured in vitro, and treated with lipopolysaccharide and TNF-α to induce CD73 detachment from RPE surface. According to whether MMP-9 inhibitor CTK8G1150 was added at the same time (the final concentration was 5.0 mol/L) or not, RPE cells cultured in the two types of mice were respectively set as MMP-9 inhibitor intervention group and non-intervention control group. The cells in each group were treated with the intervention of a solvent, 1 μmol/Ladenosine monophosphate (AMP), 1 μmol/L AMP, and 3 μmol/L 5' -α,β-methylene adenosine diphosphate (APCP) (AMP+APCP). The stimulating effect of RPE cells in different groups on CD4+ T cell proliferation was detected by tritiated thymidine incorporation. Adoptive immune induced EAU in wild-type B6 mice and CD73-/- mice, respectively. The receptor mice were randomly divided into the MMP-9 inhibitor intervention group and the non-intervention control group, and CTK8G1150 or the solvent were injected into the subretinal cavity 4, 7 and 10 days after adoptive immunity. CD73 mRNA and protein expression in RPE cells of recipient mice were detected by real-time quantitative PCR (RT-PCR) and Western blot. One-way ANOVA was used to analyze all experimental data. Results When the stimulation mode was AMP, the proliferation of CD4+ T cells in the C57BL/6 MMP-9 inhibitor intervention group decreased significantly compared with the nonintervention group (F=13.28, P 0.05). There was no statistically significant difference in the proliferation capacity of CD4+ T cells between the CD73-/- MMP-9 inhibitor intervention group and the non-intervention group (F=5.24, 6.12, 7.04; P>0.05). RT-PCR results showed that there was no statistically significant difference in the relative expression of CD73 mRNA in RPE cells between the MMP-9 inhibitor group and the non-intervention control group(F=6.54, P>0.05). Western blot results showed that the expression of CD73 protein in RPE cells in the MMP-9 inhibitor group of B6 receptor mice was significantly increased compared with the control group (F=15.24, P<0.01). Conclusion MMP-9 inhibitor blocks CD73 detachment from RPE cells surface and has a protective effect on EAU. Key words: Matrix metalloproteinase 9/antagonists & inhibitors; 5'-nucleotidase; Retinal pigment epithelium; Cells, cultured; Uveitis/physiopathology; Animal experimentation

Targeting CD6 for the treatment of experimental autoimmune uveitis

ObjectiveCD6 is emerging as a new target for treating many pathological conditions in which T cells are integrally involved, but even the latest data from studies of CD6 gene engineered mice were still contradictory. To address this issue, we studied experimental autoimmune uveitis (EAU), a model of autoimmune uveitis, in wild-type (WT) and CD6 knockout (KO) mice. MethodsAfter EAU induction in WT and CD6 KO mice, we evaluated ocular inflammation and compared retinal antigen-specific T-cell responses using scanning laser ophthalmoscopy, spectral-domain optical coherence tomography, histopathology, and T cell recall assays. Uveitogenic T cells from WT and CD6 KO mice were adoptively transferred into WT naïve mice to confirm the impact of CD6 on T cells. In addition, we immunized CD6 KO mice with recombinant CD6 protein to develop mouse anti-mouse CD6 monoclonal antibodies (mAbs) in which functional antibodies exhibiting cross-reactivity with human CD6 were screened and identified for treatment studies. ResultsIn CD6 KO mice with EAU, we found significantly decreased retinal inflammation and reduced autoreactive T-cell responses, and confirmed the impaired uveitogenic capacity of T cells from these mice in an adoptive transfer experiment. Notably, one of these cross-reactive mAbs significantly ameliorated retinal inflammation in EAU induced by the adoptive transfer of uveitogenic T cells. ConclusionsTogether, these data strongly suggest that CD6 plays a previously unknown, but pivotal role in autoimmune uveitis, and may be a promising new treatment target for this blinding disease. In addition, the newly developed mouse anti-mouse/human CD6 mAbs could be valuable tools for testing CD6-targeted therapies in other mouse models of human diseases.

Intravitreal injection of anti-Interleukin (IL)-6 antibody attenuates experimental autoimmune uveitis in mice

PurposeTo evaluate the effect of an intravitreally applied anti-IL-6 antibody for the treatment of experimental autoimmune uveitis (EAU). MethodsEAU was induced in female B10.RIII mice by Inter-Photoreceptor-Binding-Protein (IRBP) in complete Freund’s adjuvant, boosted by Pertussis toxin. Single blinded intravitreal injections of anti-IL-6 antibody were applied 5–7days as well as 8–10days (3day interval) after EAU induction into the randomized treatment eye and phosphate buffered saline (PBS) into the fellow control eye. Clinical and fluorescein angiography scoring (6 EAU grades) was done at each injection day and at enucleation day 14. Enucleated eyes were either scored histologically (6 EAU grades) or examined by ELISA for levels of IL-6, IL-17 and IL-6 soluble Receptor (sIL-6R). ResultsUveitis developed in all 12 mice. Clinical uveitis score was significantly reduced (p=0.035) in treated eyes (median 2.0, range 0–4.0, n=12) compared to the fellow control eyes (median 3.0, range 1.0–4.0, n=12). Angiography scores were reduced in 9/12 treated eyes and histological scores in 3/4 treated eyes compared to the fellow control eyes. Cytokine levels were determined in 8 mice, of which 4 responded to anti-IL-6 treatment and 4 did not respond. All mice responding to treatment had a significant reduction of IL-6 (p<0.01) and IL-17 (p=0.01) levels in treated eyes compared to the fellow control eyes. This difference was not seen in non-responding mice. ConclusionsIntravitreal anti-IL-6 treatment significantly attenuates experimental autoimmune uveitis in mice. EAU activity correlates with ocular IL-6 and IL-17 levels.

Novel CD28 antagonist mPEG PV1-Fab' mitigates experimental autoimmune uveitis by suppressing CD4+ T lymphocyte activation and IFN-γ production.

Autoimmune Uveitis is an important chronic inflammatory disease and a leading cause of impaired vision and blindness. This ocular autoimmune disorder is mainly mediated by T CD4+ lymphocytes poising a TH1 phenotype. Costimulatory molecules are known to play an important role on T cell activation and therefore represent interesting therapeutical targets for autoimmune disorders. CD28 is the prototypical costimulatory molecule for T lymphocytes, and plays a crucial role in the initiation, and maintenance of immune responses. However, previous attempts to use this molecule in clinical practice achieved no success. Thus, we evaluated the efficacy of mPEG PV1-Fab’ (PV1), a novel selective CD28 antagonist monovalent Fab fragment in the treatment of Experimental Autoimmune Uveitis (EAU). Here, we showed that PV1 treatment decreases both average disease score and incidence of EAU. A decrease in the activation profile of both T CD4+ and T CD8+ eye-infiltrating lymphocytes was evidenced. In the periphery, T CD4+ cells from PV1-treated mice also showed a decrease in their activation status, with reduced expression of CD69, CD25, and PD-1 molecules. This suppression was not dependent on Treg cells, as both their frequency and absolute number were lower in PV1-treated mice. In addition, frequency of CD4+IFN-γ+ T cells was significantly lower in PV1-treated group, but not of IL-17-producing T cells. Moreover, after specific restimulation, PV1 blockade selectively blocked IFN-γ production by CD4+ lymphocytes Taken together, our data suggest that mPEG PV1-Fab’ acts mainly on IFN-γ-producing CD4+ T cells and emphasize that this specific CD28 blockade strategy is a potential specific and alternative tool for the treatment of autoimmune disorders in the eye.

Effective Arrestin–Specific Immunotherapy of Experimental Autoimmune Uveitis with RTL: A Prospect for Treatment of Human Uveitis

To evaluate the immunotherapeutic efficacy of recombinant T cell receptor ligands (RTLs) specific for arrestin immunity in treatment of experimental autoimmune uveitis (EAU) in humanized leukocyte antigen (HLA-DR3) transgenic (Tg) mice. We generated de novo recombinant human DR3-derived RTLs bearing covalently tethered arrestin peptides 291-310 (RTL351) or 305-324 (RTL352). EAU was induced by immunization of HLA-DR3 mice with arrestin or arrestin peptide and treated with RTLs by subcutaneous delivery. T cell proliferation and cytokine expression was measured in RTL-treated and control mice. RTL351 prevented the migration of cells outside of the spleen and the recruitment of inflammatory cells into the eye, and provided full protection against inflammation from EAU induced with arrestin or arrestin peptides. RTL351 significantly inhibited T cell proliferation and secretion of inflammatory cytokines interleukin 2 (IL-2), interferon γ (IFN-γ), IL-6, and IL-17 and chemokines (macrophage inflammatory proteins [MIP-1a] and regulated and normal T cell expressed and secreted [RANTES]), which is in agreement with the suppression of intraocular inflammation. RTL350 ("empty," no peptide) and RTL352 were not effective. Immunotherapy with a single RTL351 successfully prevented and treated arrestin-induced EAU in HLA-DR3 mice and provided proof of concept for therapy of autoimmune uveitis in human patients. The beneficial effects of RTL351 should be attributed to a significant decrease in Th1/Th17 mediated inflammation. Successful therapies for autoimmune uveitis must specifically inhibit pathogenic inflammation without inducing generalized immunosuppression. RTLs can offer such an option. The single retina-specific RTLs may have a value as potential immunotherapeutic drug for human autoimmune uveitis because they effectively prevent disease induced by multiple T cell specificities.

Treatment of experimental autoimmune uveitis in rats with arsenic trioxide

目的 探讨三氧化二砷(As2O3)对实验性自身免疫性葡萄膜炎(EAU)大鼠模型的治疗作用.方法 将光感受器间维生素A类结合蛋白(IRBP)R14多肽免疫大鼠随机分为高剂量As2O3组、低剂量As2O3组、环孢素A(CsA)组和生理盐水组4组,每组5只,分别腹腔注射5mg/kg As2O3、0.5mg/kg As2O3、2mg/kg CsA及生理盐水0.2mL.裂隙灯显微镜观察大鼠眼前房炎症情况,第14天时处死大鼠,光学显微镜观察大鼠眼球的病理变化程度,免疫组织化学观察大鼠眼球中CD3+ T细胞的浸润情况,TUNEL法检测大鼠视网膜组织的凋亡.结果 生理盐水组和0.5mg/kg As2O3组可见明显的虹膜充血、血管扩张和脓性渗出,5mg/kg As2O3组和CsA组前房炎症反应程度明显较轻,与生理盐水组比较,5mg/kg As2O3组和CsA组的临床评分明显降低,差异均有统计学意义(tAs2O3 5mg=-0.656,P=0.042;tCsA =-1.308,P=0.002).组织病理学评分显示各组间差异有统计学意义(F=11.297,P=0.000).与生理盐水组比较,As2O3组和CsA组的CD3+T细胞浸润明显减少.TUNEL检测细胞凋亡在各组间差异无统计学意义(P＞0.05).结论 腹腔注射As2O3可以明显抑制EAU大鼠的临床表现、病理改变及CD3+T细胞的浸润,未增加病变部位细胞的凋亡。

Immunological effects of allopurinol in the treatment of experimental autoimmune uveitis (EAU) after onset of the disease.

Allopurinol reduces oxidative tissue damage and exerts immunomodulating effects in the treatment of experimental autoimmune uveitis (EAU). However, the mechanism of the immunologic pathway remains unclear. In previous studies, treatment was started at the time of immunization. Therefore, whether allopurinol prevents the onset of the disease (i.e., acts in a protective manner) is not known. Sixteen male Lewis rats were used: 6 EAU without therapy [control]; 4 EAU with allopurinol treatment starting 7 days after immunization [AL7]; and 6 EAU with allopurinol treatment starting 11 days after immunization [AL11]. Their sera were tested against Western blots of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of retinal proteins. Based on digital image analysis, analysis of discriminance was done. There were significant immunomodulating effects in both therapy groups (Wilks' lambda 0.001, P < 0.008) compared to controls. However, the effects were more pronounced in the AL7 group, where peak intensities and the number of peaks were markedly more reduced. Immunomodulating effects of allopurinol can be detected even if the therapy starts after the onset of the disease. Thus allopurinol strongly influences the immunologic mechanism in this model of autoimmune disease. In view of its minimal side effects, the drug could be a promising alternative for the therapy and prophylaxis of uveitis and other autoimmune diseases.

Immunological effect of systemically administered allopurinol in experimental autoimmune uveitis

Allopurinol shows beneficial effects in the systemic treatment of lens-induced uveitis. This is believed to be due to the reduction of oxidative tissue damage via a dose-dependent free radical scavenging ability and an immunomodulating effect. The purpose of this study was to investigate the immunological effects in experimental autoimmune uveitis after systemic treatment with allopurinol (AL) and steroids (STER). 31 male Lewis rats were immunized with crude retinal extract, Freund's Adjuvans and pertussis toxin. The rats were divided into four groups: healthy rats (BASIS, n = 3), experimental autoimmune-uveitis without therapy (EAU, n = 9), 50 mg/kg bw. allopurinol i.v. (ALSYS, n = 9), and 7.5 mg/kg bw. methylprednisolone i.v. (STSYS, n = 10). ALSYS and STSYS received five intravenous injections during the 2 weeks immunization period. The rats' sera were tested against Western Blots (WB) of electrophoretic separations of retinal proteins. Based on digital image analysis, an analysis of discriminance was performed. The multivariate analysis of discriminance revealed a significance difference between the WBs of ALSYS and STSYS (p < 0.01) compared to EAU without therapy. The number and intensity of peaks in WBs were strongly reduced in the ALSYS group compared to EAU. AL revealed a strong immunomodulating effect in the treatment of experimental autoimmune uveitis that is markedly stronger than that of steroids. Together with the antioxidative effect of allopurinol known from previous studies, this drug could be a new promising therapeutic approach in the treatment of uveitis.

Liposome-Encapsulated Clodronate Retards the Development of Experimental Autoimmune Uveitis

A study was undertaken to determine if the intravenous injection of liposome-encapsulated dichloromethylene diphosphonate (C12MDP; Clodronat), a treatment known to deplete monocytes, as well as liver and spleen macrophages, would reduce the number of macrophages in the retina of animals with experimental autoimmune uveitis (EAU) and decrease the severity of the disease. EAU was induced in Lewis rats by immunization with S-antigen (S-Ag). Monocytes and macrophages were depleted via an intravenous injection of Cl2MDP encapsulated in liposomes. Control groups included rats that received no S-Ag (n= 18), S-Ag and no treatment (n=23), S-Ag and free drug (n = 20), or empty liposomes (n=14). Treated animals received injections of the Cl2MDP-liposomes, free drug, or empty liposomes. Animals were sacrificed at 14, 21 and 28 days post-S-Ag administration. Intravenous, Cl2MDP-liposomes produced a statistically significant reduction in the severity of the EAU when compared to controls at both days 14 and 21 following S-Ag injection. Immunohistochemical staining with the monoclonal antibody EDI demonstrated that the severity of the ocular inflammatory response correlated with the number of EDI-positive cells in the retina. Following the cessation of treatment, treated animals developed disease that was as severe at day 28 as that of untreated animals at day 21. These results confirm the importance of monocytes and macrophages in EAU by demonstrating the correlation between the presence of EDI-positive cells in the retina and the resultant damage to the retina. Although the dosing regimen employed here did not provide a cure, strategies designed to prevent the local recruitment and/or activation of mononuclear phagocytes may prove to be useful in the treatment of EAU.

Treatment of experimental autoimmune uveitis in the rat with systemic succinylacetone

The effects of succinylacetone (SA) on the development of S-antigen-induced experimental autoimmune uveitis (EAU) in the rat were studied. SA totally suppressed EAU at Day 14 when animals were treated with a constant infusion of 1.80 mg/hr by an osmotic minipump. Three intervals of treatment with this dose rate were used (Day 0–7, Day 7–14, or Day 0–14) and, regardless of dosage interval, suppression of the disease was complete. There was a significant inhibition of S-antigen-induced lymphocyte proliferative responses in cells from popliteal lymph nodes ( P < 0.009) as well as a significant decrease of S-antigen antibody production. Animals treated with SA at a rate of 0.90 or 0.45 mg/hr developed EAU in a dose-related fashion. Animals treated with 1.8 mg/hr from Day 7–14 but killed at Day 30 had 100% breakthrough of the disease. Succinylacetone inhibits the expression of EAU and significantly suppresses the immune response to S-antigen. However, once therapy is discontinued the high incidence of breakthrough suggests a reversible noncytotoxic mechanism of immune modulation.

Bromocriptine and low dose cyclosporine in the treatment of experimental autoimmune uveitis in the rat.

The immunologic effects of bromocriptine and low dose cyclosporine on experimental autoimmune uveitis (EAU) induced in Lewis rats by S-antigen immunization were studied. Rats treated with a sub-optimal dose (low dose) of cyclosporine (2 mg/kg per d), bromocriptine (1.8 mg/kg per d), or both drugs were compared with untreated rats in regard to the development of EAU, lymphocyte proliferative responses, and anti-S-antigen serum antibodies. Bromocriptine alone decreased the incidence of EAU only in female rats (P less than 0.01), did not effect the lymphocyte proliferative response, but did significantly decrease antibody titers in both males (P less than 0.004) and females (P less than 0.0005). Low dose cyclosporine also partially decreased the incidence of EAU in female rats, but did not decrease antibody titers or lymphocyte proliferative responses. Bromocriptine plus low-dose cyclosporine led to more marked decreases in the incidence of EAU and anti-S-antigen antibody titers as well as in the lymphocyte proliferative assay (P less than 0.01 for males, P less than 0.0005 for females). This study suggests that bromocriptine can enhance the immunosuppression of low dose cyclosporine.