Anti-CD40 monoclonal antibody ameliorates experimental autoimmune uveoretinitis in mice.

OBJECTIVE: To investigate the effects of CD40 on ocular inflammation in experimental autoimmune uveoretinitis (EAU) in B10.RIII mice. ANIMALS STUDIED: EAU-susceptible B10.RIII mice were subcutaneously immunized with interphotoreceptor retinoid-binding protein (IRBP) 161-180 in complete Freund's adjuvant and evaluated clinically and pathologically on days 7, 14, 21, 28, and 35 postimmunization. Anti-CD40 antibody was intraperitoneally injected into mice every other day from days 7 to 14 postimmunization. Phosphate-buffered saline (PBS)-injected EAU mice were used as the controls. PROCEDURES: The frequencies of CD11c+ CD40+ dendritic cells (DCs), CD11c+ MHC-II+ DCs, and CD11c+ CD40+ MHC-II+ DCs in splenocytes were evaluated by flow cytometry on days 0, 7, 14, and 21 after immunization. Tumor necrosis factor (TNF)-α and interleukin (IL)-6 production in CD11c+ DCs was assessed by ELISA. IRBP-specific lymphocyte proliferation was assessed using a modified MTT cell proliferation assay. RESULTS: The number of CD11c+ CD40+ DCs, CD11c+ MHC-II+ DCs, and CD11c+ CD40+ MHC-II+ DCs increased at the onset of EAU, peaked at the height of disease severity, and was sustained at a high level until day 21. Treatment with anti-CD40 antibody significantly alleviated clinical and pathological activities related to EAU. Compared with the control mice, antibody-treated EAU mice showed few CD11c+ CD40+ DC and CD11c+ CD40+ MHC-II+ DC frequencies in splenocytes. The anti-CD40 antibody significantly suppressed IRBP-specific lymphocyte proliferation and TNF-α and IL-6 production by DCs in EAU mice. CONCLUSIONS: The increased expression of CD40 and major histocompatibility complex (MHC) class II molecules in the splenocytes of EAU mice were correlated with inflammatory activity. Anti-CD40 treatment can significantly attenuate EAU activity by inhibiting systemic IRBP-specific immune responses.

Calcium dobesilate prevents the oxidative stress and inflammation induced by diabetes in the retina of db/db mice.

AIM: Calcium dobesilate (CaD) is beneficial in early stages of diabetic retinopathy (DR), but its mechanisms of action remains to be elucidated. The aim was to investigate the effect of CaD on proinflammatory cytokines and oxidative stress. METHODS: db/db mice were randomly assigned to daily oral treatment with CaD (200mg/kg/day) or vehicle for 15days. Biomarkers of oxidative stress (dihydroethidium, malondialdehyde), NF-κB, and proinflammatory cytokines (IL-1ß, IL-6, IL-8, TNF-α, MCP-1) were examined in the retina by immunohistochemical analysis. Cultures of human retinal endothelial cells (HRECs) were used for complementary experiments. RESULTS: CaD significantly reduced the biomarkers of oxidative stress in the retina of db/db mice. In addition, CaD prevented the increase of NF-κB, IL-6, IL-8, TNF-α and MCP-1 induced by diabetes. CaD inhibited the activation of NF-kß induced by IL-1ß by preventing IKKB-α phosphorylation in HRECs and reduced the upregulation of IL-6 and IL-18 induced by TNF-α in a dose-dependent manner. CONCLUSION: Our results suggest that antioxidant and antiinflammatory effects are crucial in accounting for the effectiveness of CaD for treating DR.

Mimicry epitope from Ehrlichia canis for interphotoreceptor retinoid-binding protein 201-216 prevents autoimmune uveoretinitis by acting as altered peptide ligand.

We report here identification of novel mimicry epitopes for interphotoreceptor retinoid-binding protein (IRBP) 201-216, a candidate ocular antigen that causes experimental autoimmune uveoretinitis (EAU) in A/J mice. One mimicry epitope from Ehrlichia canis (EHC), designated EHC 44-59, induced cross-reactive T cells for IRBP 201-216 capable of producing T helper (Th)1 and Th17 cytokines, but failed to induce EAU in A/J mice. In addition, animals first primed with suboptimal doses of IRBP 201-216 and subsequently immunized with EHC 44-59 did not develop EAU; rather, the mimicry epitope prevented the disease induced by IRBP 201-216. However, alteration in the composition of EHC 44-59 by substituting alanine with valine at position 49, similar to the composition of IRBP 201-216, enabled the mimicry epitope to acquire uveitogenicity. The data provide new insights as to how microbes containing mimicry sequences for retinal antigens can prevent ocular inflammation by acting as naturally occurring altered peptide ligands.

Contribution of CD4+CD25+ T cells to the regression phase of experimental autoimmune uveoretinitis.

PURPOSE: To investigate the role of CD4(+)CD25(+) Treg cells in the development of experimental autoimmune uveoretinitis (EAU). METHODS: EAU was induced in B10RIII mice by immunization with IRBP(161-180) in complete Freund's adjuvant and evaluated clinically and pathologically on days 0, 7, 14, 21, and 28. Lymphocytes from draining lymph nodes (LNs) were subjected to flow cytometry to analyze the frequency of CD4(+)CD25(+) Treg cells. CD4(+)CD25(+) Treg cells and CD4(+)CD25(-) T cells were separated by means of magnetic-assisted cell sorting and cocultured or crossover cultured for 3 days. Proliferation of CD4(+)CD25(-) T cells was measured using a modified MTT assay. The levels of IFN-gamma and IL-17 in the supernatants were determined by enzyme-linked immunosorbent assay. RESULTS: Clinical and histopathologic results showed a severe intraocular inflammation in the immunized mice. The frequency of CD4(+)Foxp3(+) T cells and CD4(+)CD25(+)Foxp3(+) T cells in the draining LN lymphocytes was increased on day 7, reached its peak on day 14, and maintained a high level up to day 42. CD4(+)CD25(+) Treg cells obtained from mice on days 14 and 28 after immunization showed a stronger inhibitory effect on the proliferation of CD4(+)CD25(-) T cells and the production of IFN-gamma by CD4(+)CD25(-) T cells compared with those obtained from control mice. CD4(+)CD25(+) Treg cells did not affect IL-17 production. Transfer of CD4(+)CD25(+) Treg cells obtained from EAU mice was able to suppress EAU induction by IRBP(161-180) that was not observed after transfer of cells from mice that had received CFA alone, suggesting antigen specificity of the Treg response. CONCLUSIONS: A significantly increased frequency and immunoregulatory action of CD4(+)CD25(+) Treg cells is associated with the development and regression of EAU, suggesting that CD4(+)CD25(+) Treg cells are induced during EAU and may be involved in its regression.

Down-regulation of inducible co-stimulator (ICOS) by intravitreal injection of small interfering RNA (siRNA) plasmid suppresses ongoing experimental autoimmune uveoretinitis in rats.

BACKGROUND: RNA interference (RNAi) is now being exploited as a powerful tool for gene knockdown. Recently, we had shown that inducible co-stimulator (ICOS) was up-regulated in experimental autoimmune uveoretinitis (EAU). The aim of this study was to investigate whether intravitreal injection of small interfering RNA (siRNA) plasmid, targeting ICOS, suppresses the ongoing experimental autoimmune uveoretinitis (EAU) in rats. METHODS: Oligonucleotide targeting ICOS was cloned into linearized pRNAT-U6.1/Neo eukaryotic expression vector to construct the recombinant plasmid (pRNAT-U6.1/Neo-ICOS). After transfecting activated rat T cells with the recombinant plasmid, ICOS mRNA and protein expression levels were determined by real-time RT-PCR and Western blot analysis respectively. Rats were immunized with IRBP R16 peptide emulsified in complete Freund's adjuvant (CFA) and given an intravitreal injection of pRNAT-U6.1/Neo-ICOS on day 6 after immunization. After 13days of immunization, the ICOS protein expression and CD4(+) ICOS (+) T cells were identified in retinae through Western blot analysis and flow cytometry respectively. Intraocular inflammation was assessed by the scores of the clinical and histological appearances. Delayed-type hypersensitivity (DTH) and lymphocyte proliferation were detected to evaluate the systemic effect of intravitreal injection of pRNAT-U6.1/Neo-ICOS. RESULT: The recombinant plasmid (pRNAT-U6.1/Neo-ICOS) for the ICOS siRNA was successfully constructed. In vitro studies using the recombinant plasmid has showed the down-regulation of ICOS gene expression both at the mRNA and protein levels. Clinical and pathological scores showed that ocular inflammation of pRNAT-U6.1/Neo-ICOS-treated eyes was markedly less than that of vehicle-treated eyes. The expression of ICOS protein and the amount of CD4(+) ICOS(+) T cells in retinae significantly decreased by intravitreal injection of the recombinant plasmid, whereas delayed-type hypersensitivity response and lymphocyte proliferation were not impaired in rats treated with the recombinant plasmid. CONCLUSION: Intravitreal injection of siRNA plasmid targeting ICOS effectively down-regulated the expression of ICOS, and was highly effective in suppressing the ongoing process of EAU without any side-effects on systemic cellular immunity.

LX211 (voclosporin) suppresses experimental uveitis and inhibits human T cells.

PURPOSE: To test the therapeutic effectiveness of voclosporin against experimental autoimmune uveoretinitis (EAU) in rats and to evaluate its effect on human T cells. METHODS: EAU was induced by immunization with a uveitogenic protein. Voclosporin administration, by subcutaneous injection, began on day (d) 0 or d7 after immunization. Treatment effectiveness was evaluated in vivo using clinical EAU scoring (d7-d13) and histopathologic evaluation of enucleated eyes after experimental termination. Rodent lymphocytes were harvested from lymph nodes on d14 for antigen-specific proliferation assays. The effect of voclosporin on human T-cell proliferation and cytokine secretion was examined in vitro. RESULTS: Voclosporin prevented EAU development in rats receiving medium and high preventive doses, whereas high-dose voclosporin administration effectively treated EAU. Lymphocytes from animals treated with voclosporin had decreased antigen-specific proliferation in vitro compared with lymphocytes from untreated animals. No evidence of abnormal ocular histopathology was found in the eyes from animals that received high doses of therapeutic voclosporin. Using human T cells, voclosporin inhibited human T-cell proliferation up to 100-fold. Furthermore, voclosporin treatment of human T cells significantly reduced pan T-cell effector responses. CONCLUSIONS: Voclosporin effectively suppressed uveoretinitis in an animal model that imitates the human inflammatory ocular disease by inhibiting lymphocyte proliferation. In addition, voclosporin effectively inhibited human T-cell proliferation and function in vitro. The authors report the first evidence supporting the application of voclosporin to treat intraocular inflammation.

Role of T-cell receptor V beta 8.3 peptide vaccine in the prevention of experimental autoimmune uveoretinitis.

BACKGROUND: T-cell receptor (TCR) plays an important role in the development of autoimmune diseases. Recently, it was reported that immunization of animals with TCR peptide derived from the pathogenic cells could prevent autoimmune diseases. The aim of this study was to investigate whether vaccination with a synthetic peptide from the hypervariable region of TCR V(beta) 8.3, an experimental autoimmune uveoretinitis (EAU)-associated gene, was able to prevent the disease. METHODS: EAU was induced in Lewis rats by immunization with IRBP R16 peptide emulsified in complete Freund's adjuvant (CFA). The clinical and histological appearances were scored. Delayed type hypersensitivity (DTH) and lymphocyte proliferation were detected. Cytokine levels of aqueous humour, supernatants of cells from spleen and draining lymph nodes were measured by enzyme linked immunosorbent assay (ELISA). Gene expression of TCR V(beta) 8.3 on CD(4)(+) T cells was examined by real time quantitative polymerase chain reaction (PCR). RESULTS: After vaccination, the intraocular inflammation was significantly mitigated, antigen specific DTH and lymphocyte proliferation responses were suppressed, interleukin (IL)-2 in aqueous humour, interferon (IFN)-gamma and IL-2 produced by the spleen and draining lymph node cells were significantly decreased, whereas the production of IL-4 and IL-10 were increased. The response of draining lymph node cells to TCR V(beta) 8.3 peptide was enhanced after vaccination. Inoculation with CFA alone did not affect the severity of EAU and the above parameters. The suppression of EAU was much stronger in the group of four fold inoculations than the group of two fold inoculations. The expression of TCR V(beta) 8.3 gene was significantly reduced in the group of fourfold inoculations. CONCLUSION: Vaccination with the synthetic TCR V(beta) 8.3 peptide could remarkably inhibit the development of EAU.

Oral administration of interferon-beta suppresses experimental autoimmune uveoretinitis.

BACKGROUND: The oral administration of type I interferons (IFNs) have been reported to reduce severity of inflammation in several animal models of autoimmune disease. This study examined whether oral administration of IFN-beta is capable of modulating inflammation in experimental autoimmune uveoretinitis (EAU). METHODS: EAU was induced in rats by immunization with interphotoreceptor retinoid-binding protein (IRBP) emulsified in complete Freund's adjuvant. Rats were treated with either varying doses (10(2), 10(3), 10(4) or 10(5)IU) of mouse recombinant IFN-beta or phosphate-buffered saline for control, via direct oropharyngeal application once a day for 28 days starting 7 days before IRBP immunization. Intraocular inflammation was assessed by slit-lamp biomicroscopy and histopathological examination. Spleen cell proliferation response and cytokine production under IRBP stimulation were assessed. Spleen cell subpopulations were also measured. RESULTS: IFN-beta at doses of either 10(4) or 10(5) IU significantly reduced both the clinical and histopathological severity of EAU. Spleen cell proliferation and IFN-gamma production from rats treated with 10(4) IU IFN-beta were significantly decreased compared with controls. Furthermore, the proportion of both NK cells and NKT cells in the spleen of rats treated with IFN-beta was increased compared with controls. CONCLUSION: These results suggest that the oral administration of IFN-beta reduces inflammation in IRBP-mediated EAU and that the mechanism of this action may involve NK cells and NKT cells.

Intravitreal toxicology and duration of efficacy of a novel antiviral lipid prodrug of ganciclovir in liposome formulation.

PURPOSE: To evaluate the intraocular safety and antiviral treatment efficacy of the sustained lipid prodrug of ganciclovir, 1-O-hexadecylpropanediol-3-phospho-ganciclovir (HDP-P-GCV), as an intravitreal injectable drug system for viral retinitis. METHODS: HDP-P-GCV was synthesized by coupling 1-O-hexadecyl-propanediol-3-phosphate to either free hydroxyl of ganciclovir in pyridine with dicyclohexylcarbodiimide as catalyst. The compound was formulated into liposomes. The antiviral activity was assessed by DNA reduction in vitro, and intraocular safety was assessed by ophthalmoscopy, electrophysiology, and histology after intravitreal injections, with resultant intravitreal concentrations of 0.2, 0.632, 1.12, and 2 mM. The treatment efficacy was evaluated by simultaneous intravitreal injection of HDP-P-GCV and herpes simplex virus type 1 (HSV-1) or by intravitreal injection of HDP-P-GCV at various times before HSV-1 intravitreal inoculation. Retinitis was scored with ophthalmoscopy and compared with controls. RESULTS: In vitro, the IC50 of HDP-P-GCV against HSV-1 and human cytomegalovirus (HCMV) infected cells was 0.02 and 0.6 microM, respectively. In rabbits in vivo, HDP-P-GCV dispersed evenly and maintained a good vitreous clarity at all doses except 2 mM final intravitreal concentration. Although cataracts were observed in some eyes at the higher doses, they were not observed in eyes with 0.2 mM final intravitreal concentration. No other indications of ocular toxicity were observed. Intravitreal injection of HDP-P-GCV with resultant 0.2 mM intravitreal concentration in the HSV-1 retinitis rabbit model demonstrated a complete protection of the retina with the simultaneous treatment strategy and a 4 (P = 0.03) to 6-(P = 0.058) week significant protection of retina with the pretreatment strategies when compared with ganciclovir or blank liposome controls. CONCLUSIONS: In the rabbit model of HSV-1 retinitis HDP-P-GCV acts as a long-lasting intravitreal injectable anti-CMV or anti-HSV compound. This self-assembling liposome system could be applicable for many compounds available for intraocular diseases.

Effects of monoclonal antibodies directed at cell surface molecules on murine experimental autoimmune uveoretinitis.

BACKGROUND: To elucidate the immunopathogenic mechanism of endogenous uveitis, the effects of monoclonal antibodies to molecules involved in the immune response were studied in murine experimental autoimmune uveoretinitis (EAU). METHODS: Monoclonal antibodies to CD4, CD8, Ia(k), Ia(d), lymphocyte function-associated antigen-1 (LFA-1), and intercellular adhesion molecule-1 (ICAM-1) were used in this study. The monoclonal antibodies were added in the culture of lymph node cells from B10.BR mice(H-2(K)) immunized with interphotoreceptor retinoid-binding protein (IRBP) and the inhibition of proliferative response was measured. In vivo, IRBP-immunized mice were treated with a high dose of the antibody, and the EAU induction was examined both clinically and pathologically. RESULTS: Proliferative response of IRBP-sensitized lymph node cells was inhibited strongly by anti-CD4 or anti-LFA-1 monoclonal antibody and moderately by anti-Ia(k) or anti-ICAM-1 monoclonal antibody. In contrast, no inhibitory effect of anti-CD8 or anti-Ia(d) monoclonal antibody was observed. In vivo treatment with anti-CD4 monoclonal antibody inhibited development of EAU in a dose-dependent manner, while in vivo treatment with other monoclonal antibodies did not cause significant suppression of EAU. CONCLUSIONS: CD4, Ia, LFA-1, and ICAM-1 molecules play important roles in the antigen-specific immune response of lymphocytes. However, in in vivo treatment with monoclonal antibodies to these molecules, only anti-CD4 monoclonal antibody had a strong inhibitory effect on the development of EAU.

Immunomodulatory effects of linomide in animals immunized with immunopathogenic retinal antigens: dissociation between different immune functions.

Linomide (LS-2616, quinoline-3-carboxamide) has been reported to exert a diverse range of effects on the immune system. On one hand, this drug was found to stimulate the immune system and to enhance activities such as DTH or allograft rejection. On the other hand, linomide was shown to inhibit the induction of experimental autoimmune encephalomyelitis and myasthenia gravis, as well as the development of diabetes in non-obese diabetic (NOD) mice. Here we report the effects of linomide in animals immunized with uveitogenic retinal antigens. Treatment with linomide completely inhibited the development of experimental autoimmune uveoretinitis (EAU) in mice immunized with interphotoreceptor retinoid-binding protein and markedly suppressed EAU in rats immunized with S-antigen (S-Ag). In addition, linomide-treated rats exhibited reduced antibody production and lymphocyte proliferative response to S-Ag. In contrast to these suppressive activities, linomide treatment did not affect the development of adoptively transferred EAU in rats and moderately enhanced the DTH reactions to S-Ag in immunized rats in which EAU and other immune responses to this antigen were suppressed.

Immunomodulation of experimental autoimmune uveoretinitis by intravenous injection of uveitogenic peptides.

Intravenous (IV) injection of antigenic proteins induces specific unresponsiveness, as shown by the diminished response to a challenge with these proteins in complete Freund's adjuvant. This study examined the effect of IV treatment with uveitogenic peptides on the development of experimental autoimmune uveoretinitis (EAU). The peptides used were derived from the sequence of bovine interphotoreceptor retinoid-binding protein (IRBP) and included R16 (sequence, 1177-1191), which is immunodominant and highly uveitogenic, and R4 (sequence, 1158-1180), which is nondominant and weakly uveitogenic. The efficacy of this treatment was found to depend on both the dose used for the IV injection and that used for the challenge. Thus, EAU induced by R16 at a dose of 0.2 nmol/rat was inhibited completely in all rats treated with the peptide at doses of 400 or 133 nmol and partially by the low dose of 5 nmol/rat. However, the EAU induced by a R16 challenge of 40 nmol/rat was inhibited only partially by the high treatment dose of 400 nmol/rat. The IV treatment was found to be effective in inhibiting the EAU induced by peptide R4. A large dose of R4 was needed to induce EAU (40 nmol/rat), and the disease was inhibited completely in all rats treated IV with this peptide at doses of 800, 400, or 133 nmol. In most animals injected with the 44-nmol dose, also, inhibition was complete. These data show that there is a correlation between the doses needed for achieving inhibition and those used for the challenge. The ratios between these doses in all experiments were found within the range 1-20.(ABSTRACT TRUNCATED AT 250 WORDS)

Trials of vaccination against experimental autoimmune uveoretinitis with a T-cell receptor peptide.

T lymphocytes which mediate several experimental autoimmune diseases, including encephalomyelitis (EAE) and uveoretinitis (EAU) in Lewis rats, preferentially utilize V beta 8 gene product in their receptor. Vaccination against a V beta 8.2-derived peptide was reported to inhibit EAE induction and we report here on the effect of vaccination with this peptide on the development of EAU. Experimental rats were pretreated with the V beta 8.2 peptide, emulsified in adjuvant (CFA), whereas control animals were untreated or injected with saline in CFA. Rats of all groups were immunized 30 or 40 days later with the immunopathogenic antigen, emulsified in Mycobacterium-enriched CFA. Vaccination with CFA emulsions containing either the V beta 8.2 peptide or saline, remarkably inhibited the development of the tested diseases, as compared to the untreated controls. Vaccination with the V beta 8.2 peptide had variable effects in this study on disease development: it inhibited the S-antigen-induced EAU more than did treatment with CFA in four out of six experiments, had a similar effect to that of CFA in one experiment and enhanced the disease in another experiment. Conversely, vaccination with the V beta 8.2 peptide slightly enhanced the EAU induced by the interphotoreceptor retinoid-binding protein (IRBP), or its dominant determinant, in three of four experiments and had no apparent effect in the fourth experiment. In addition, we could not reproduce the reported protective effect of vaccination with the V beta 8.2 peptide against induction of EAE. Vaccination with the V beta 8.2 peptide also had no clear effect on the development of humoral or cellular immune responses against S-antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Suppression of S antigen-induced uveitis by vitamin E supplementation.

The anti-inflammatory effects of vitamin E were investigated using the S antigen model of uveoretinitis. Thirty-six 3-week-old Lewis rats were separated into three groups and maintained on a specially formulated diet. One group of animals received a diet deficient in vitamin E; a second group received a normal diet containing vitamin E, and the third group, in addition to receiving the normal diet, received vitamin E supplementation. At 9 weeks of age, all rats were sensitized to S antigen. Six animals in each group were killed on day 14 and the remaining animals on day 21 following immunization. Both histopathologic and biochemical studies were conducted to evaluate the tissue damage observed in animals maintained on different dietary levels of the vitamin. The intraocular inflammation in the vitamin E-supplemented group was considerably smaller than in the other two groups (p less than 0.01). The former group had the highest level of vitamin E in both the eye and plasma (mean value 1.13 micrograms/mg protein and 23.9 micrograms/ml, respectively), while the vitamin E-deficient group had the lowest levels (mean values of 0.16 micrograms/mg protein and 0.48 micrograms/ml in the eye and plasma, respectively). Results of the radioimmunoassay for the determination of the arachidonic acid metabolites revealed significantly lower levels of thromboxane B2 in the vitamin E-supplemented group (2.04 +/- 0.45 pg/mg) than in the normal (4.33 +/- 0.98 pg/mg) or the vitamin E-deficient (5.21 +/- 1.12 pg/mg) groups (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)