Ongoing Experimental Allergic Encephalomyelitis Research Articles

Dendritic cells, engineered to overexpress 25-hydroxyvitamin D 1α-hydroxylase and pulsed with a myelin antigen, provide myelin-specific suppression of ongoing experimental allergic encephalomyelitis.

Multiple sclerosis (MS) is caused by immune-mediated damage of myelin sheath. Current therapies aim to block such immune responses. However, this blocking is not sufficiently specific and hence compromises immunity, leading to severe side effects. In addition, blocking medications usually provide transient effects and require frequent administration, which further increases the chance to compromise immunity. In this regard, myelin-specific therapy may provide the desired specificity and a long-lasting therapeutic effect by inducing myelin-specific regulatory T (Treg) cells. Tolerogenic dendritic cells (TolDCs) are one such therapy. However, ex vivo generated TolDCs may be converted into immunogenic DCs in a proinflammatory environment. In this study, we identified a potential novel myelin-specific therapy that works with immunogenic DCs, hence without the in vivo conversion concern. We showed that immunization with DCs, engineered to overexpress 25-hydroxyvitamin D 1α-hydroxylase for de novo synthesis of a focally high 1,25-dihydroxyvitamin D concentration in the peripheral lymphoid tissues, induced Treg cells. In addition, such engineered DCs, when pulsed with a myelin antigen, led to myelin-specific suppression of ongoing experimental allergic encephalomyelitis (an MS animal model), and the disease suppression depended on forkhead-box-protein-P3(foxp3)+ Treg cells. Our data support a novel concept that immunogenic DCs can be engineered for myelin-specific therapy for MS.—Li, C.-H., Zhang, J., Baylink, D. J., Wang, X., Goparaju, N. B., Xu, Y., Wasnik, S., Cheng, Y., Berumen, E. C., Qin, X., Lau, K.-H. W., Tang, X. Dendritic cells, engineered to overexpress 25-hydroxyvitamin D 1α-hydroxylase and pulsed with a myelin antigen, provide myelin-specific suppression of ongoing experimental allergic encephalomyelitis.

Effect of oral administration of pig spinal cord hydrolysate on clinical and histopathological symptoms of experimental allergic encephalomyelitis in rats.

Oral tolerance is the natural occurring phenomenon of a decreased immune response to previously fed antigens, which prevents induction of a response to dietary antigens. One of the mechanisms is deletion of T lymphocytes reactive to the fed antigen. Knowing that phenomenon, it seems appropriate to engage this mechanism for treatment of autoimmune diseases. Multiple sclerosis (MS) is an autoimmunological disease which causes neurological impairment in humans. Autoreactive T lymphocytes migrate through the open blood-brain barrier into the central nervous system (CNS), where they recognize myelin antigens as foreign, and induce an inflammatory response against the myelin sheath, which causes demyelination and even axonal loss. Experimental allergic encephalomyelitis (EAE), an animal model of MS, resembles the autoimmunological aspect of the disease. We used a broad spectrum of myelin antigens to induce EAE, and also to induce oral tolerance by giving myelin epitopes intragastrically to rats. The aim of our study was to evaluate whether pig spinal cord hydrolysate given intragastrically is able to evoke oral tolerance in rats with an animal model of MS - EAE. In our experiments we fed female Lewis rats with pig spinal cord hydrolysate at doses of 5, 20 and 100 mg per kg of body weight. We observed diminished clinical symptoms of ongoing EAE in rats fed with all doses of pig spinal cord hydrolysate. In the histopathological study, intensity of the inflammatory process in spinal cord was similar in rats not fed with EAE and in rats fed with lower doses of pig spinal cord hydrolysate. In animals fed with the highest dose of pig spinal cord hydrolysate, intensification of the inflammatory response was observed. These results were confirmed by morphometric evaluations. We found that feeding animals with preparations containing myelin antigens can reduce EAE symptoms, which may indicate oral tolerance induction, but the obtained results also underline the importance of dose of the orally given antigens, because of the possibility of enhancement of the inflammatory process in the CNS.

Suppression of ongoing experimental allergic encephalomyelitis in DA rats by novel peptide drug, structural part of human myelin basic protein 46–62

Previously, we demonstrated that autoantibodies (AAb) in multiple sclerosis (MS) reveal site-specific binding and cleavage toward myelin basic protein (MBP) epitope library. We have found several fragments of MBP immunodominant in terms of AAb binding. Here, we applied these peptides to DA rats with induced protracted relapsing experimental allergic encephalomyelitis (EAE) most closely related to MS. DA rats with EAE induced by syngenic spinal cord homogenate in complete Freund's adjuvant were treated by nasal route with human MBP 46–62, 81–102, 124–139, 147–170, and Copaxone®. MBP 124–139 and 147–170 displayed only mild therapeutic effects but MBP 46–62 significantly reduced EAE, reflected by lower clinical scores and shorter EAE duration compared to controls.

Dendritic cells exposed to estrogen in vitro exhibit therapeutic effects in ongoing experimental allergic encephalomyelitis

Immunomodulatory effects of estrogen have been demonstrated by clinical and experimental observations, but the mechanisms by which estrogen exhibits the effects remain to be defined. One possible mechanism by which estrogen inhibits the development of experimental allergic encephalomyelitis (EAE), a commonly used model of multiple sclerosis (MS) in humans, is over the functions of dendritic cells (DC). Here, we describe that splenic DC from Lewis rats obtained on day 12 post-immunization (p.i.) with myelin basic protein (MBP) encephalitogenic peptide 68–86+Freund's complete adjuvant (FCA), after being exposed in vitro 17β-estradiol, exhibited therapeutic effects on acute EAE when injected subcutaneously on day 5 p.i. Blood mononuclear cells (MNC) were isolated from thus treated rats on day 12 p.i. Administration of estrogen-exposed DC prevented the expansion of CD4 + T cells and increased proportions of regulatory T cells producing IL-10 and CD4 +CD28 − suppressor T cells, accompanied with increased IL-10 and IFN-γ, and reduced TNF-α production. Infiltrates of CD68 + macrophages within the central nervous system and MBP 68–86-induced T cell proliferation were inhibited in rats injected with estrogen-exposed DC compared to rats injected with naive DC. Estrogen up-regulated the expression of indoleamine 2,3-dioxygenase, which promotes tolerogenic properties of DC. The results suggest that in vitro exposure of DC to estrogen modulates DC functions and results in a therapeutic effect of DC.

Gene transfer of Ig-fusion proteins into B cells prevents and treats autoimmune diseases.

Based on the tolerogenic properties of IgG carriers and B cell Ag presentation, we developed a retrovirally mediated gene expression approach for treatment of autoimmune conditions. In this study, we show that the IgG-Ag retroviral constructs, expressing myelin basic protein (MBP) or glutamic acid decarboxylase in B cells, can be used for the treatment of murine models for multiple sclerosis and diabetes. Transduction of syngeneic B cells with MBP-IgG leads to the amelioration of ongoing experimental allergic encephalomyelitis induced by the transfer of primed cells from PLxSJL F(1) mice with ongoing disease and could be effective even after symptoms appeared. This effect is specific and does not involve bystander suppression because treatment with MBP-IgG does not affect disease induced after immunization with proteolipid protein immunodominant peptide plus MBP. Interestingly, if donor B cells are derived from gld mice (Fas ligand-negative), then tolerance is not induced with a model Ag although there was no evidence for Fas ligand-mediated deletion of target T cells. In spontaneous diabetes in nonobese diabetic mice, we were able to stop the ongoing autoimmune process by treatment at 7-10 wk with glutamic acid decarboxylase-IgG retrovirally transduced B cells, or attenuate it with B cells transduced with an insulin B chain (B9-23) epitope IgG fusion protein. Furthermore, IgG fusion protein gene therapy can also protect primed recipients from Ag-induced anaphylactic shock, and thus does not cause immune deviation. These results demonstrate proof of principle for future efforts to develop this approach in a clinical setting.

Suppression of ongoing experimental allergic encephalomyelitis (EAE) in Lewis rats: synergistic effects of myelin basic protein (MBP) peptide 68-86 and IL-4.

Mucosal myelin autoantigen administration effectively prevented EAE, but mostly failed to treat ongoing EAE. Patients with multiple sclerosis (MS), for which EAE is considered an animal model, did not benefit from oral treatment with bovine myelin. We anticipated that autoantigen, administered together with a cytokine that counteracts Th1 cell responses, might ameliorate Th1-driven autoimmune disease, and that nasal administration might considerably reduce the amounts of antigen + cytokine needed for treatment purposes. Lewis rats with EAE actively induced with myelin basic protein peptide (MBP 68-86) and Freund's complete adjuvant (FCA), received from day 7 post-immunization, i.e. after T cell priming had occurred, 120 microg MBP 68-86 + 100 ng IL-4 per rat per day for 5 consecutive days. These rats showed later onset, lower clinical scores, less body weight loss and shorter EAE duration compared with rats receiving MBP 68-86 or IL-4 only, or PBS. EAE amelioration was associated with decreased infiltration of ED1+ macrophages and CD4+ T cells within the central nervous system, and with decreased interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) and enhanced IL-4, IL-10 and transforming growth factor-beta (TGF-beta) responses by lymph node cells. Simultaneous administration of encephalitogenic peptide + IL-4 by the nasal route thus suppressed ongoing EAE and induced IL-4, IL-10 and TGF-beta-related regulatory elements.

Multi-Modal Antigen Specific Therapy for Autoimmunity

Peripheral tolerance, represents an attractive strategy to down-regulate previously activated T cells and suppress an ongoing disease. Herein, immunoglobulins (Igs) were used to deliver self and altered self peptides for efficient peptide presentation without costimulation to test for modulation of experimental allergic encephalomyelitis (EAE). Accordingly, the encephalitogenic proteolipid protein (PLP) sequence 139–151 (referred to as PLP1) and an altered form of PLP1 known as PLP-LR were genetically expressed on Igs and the resulting Ig-PLPl and Ig-PLP-LR were tested for efficient presentation of the peptides and for amelioration of ongoing EAE. Evidence is presented indicating that Ig-PLPl as well as Ig-PLP-LR given in saline to mice with ongoing clinical EAE suppresses subsequent relapses. However, aggregation of both chimeras allows crosslinking of Fcγ receptors (FcγRs) and induction of IL-10 production by APCs but does not promote the up-regulation of costimulatory molecules. Consequently, IL-10 displays bystander suppression and synergizes with presentation without costimulation to drive effective modulation of EAE. As Ig-PLP1 is more potent than Ig-PLP-LR in the down-regulation of T cells, we conclude that peptide affinity plays a critical role in this multi-modal approach of T cell modulation.

The complexicity of cytokine treatment in ongoing EAE induced with MBP peptide 68-86 in Lewis rats.

IL-10 and TGF-beta1 are important immunoregulatory cytokines associated with clinical remissions in multiple sclerosis and amelioration of experimental allergic encephalomyelitis (EAE). IL-10 and TGF-beta1 have previously been shown to prevent the development of EAE. Here, we study effects of IL-10 and TGF-beta1 in ongoing EAE. When IL-10 or TGF-beta1 was administered by the nasal route from day 0 to day 7 postimmunization (pi), both IL-10 and TGF-beta1 prevented the development of acute EAE in Lewis rats. When IL-10 or TGF-beta1 was administered by the nasal route from day 5 to day 12 pi, both IL-10 and TGF-beta1 failed to influence clinical EAE. The inhibition of clinical EAE severity in IL-10-prevented rats was associated with reduced proliferation, IFN-gamma mRNA expression, and IFN-gamma secretion, while proliferation as well as IFN-gamma mRNA expression and secretion were augmented in TGF-beta1-prevented rats. TGF-beta1-prevented rats exhibited high levels of NO production by DC, which may mediate apoptosis of CD4+ T cells and of the DC themselves. For prevention, both IL-10 and TGF-beta1 inhibited infiltration of CD4+ T cells within the CNS, but neither IL-10 nor TGF-beta1 induced immune deviation from Th1 to Th2. Expression of IL-4 mRNA was not altered in IL-10- and TGF-beta1-prevented rats. These results demonstrate that IL-10 and TGF-beta administration by the nasal route can prevent the development of acute EAE, but by different mechanisms. The findings in rats with ongoing EAE have implications for the clinical application of cytokine treatment in autoimmune diseases.

IFN-τ Suppresses Both the Autoreactive Humoral and Cellular Immune Responses and Induces Stable Remission in Mice with Chronic Experimental Allergic Encephalomyelitis

We have previously shown that interferon-τ (IFN-τ) pretreatment inhibits the development of both acute and chronic mouse experimental allergic encephalomyelitis (EAE), an animal model for the human demyelinating disease multiple sclerosis (MS). IFN-τ is a type I IFN that has pregnancy recognition hormone activity in ruminants. Here, we show that IFN-τ induced remission in SJL/J mice that had ongoing chronic active EAE disease and protected mice against secondary relapses. IFN-τ treatment reversed lymphocyte infiltration and microglial activation in the central nervous system. Mice that were treated with IFN-τ had lower levels of anti-MBP antibodies than untreated mice in both chronic and acute forms of EAE. MBP induced proliferation in B cells from EAE mice, but treatment with IFN-τ eitherin vivoorin vitroblocked activation. Furthermore, IFN-τ inhibited MBP activation of T cells from EAE mice. Thus, IFN-τ inhibits the humoral arm as well as the cellular arm of the autoimmune disease EAE. The data presented here show that IFN-τ inhibits both B cell and T cell responses in EAE as well as active, chronic EAE, and this may help explain the effectiveness of type I IFNs in treatment of MS.

Cyclosporin A treatment of an induced attack in a chronic relapsing model of experimental allergic encephalomyelitis

Chronic relapsing experimental allergic encephalomyelitis (EAE) was induced in 8-week-old SJL/J mice by injecting an encephalitogenic emulsion on Day 0 and Day 7. A third injection was given on Day 70 postinoculation (PI) which precipitated an attack with high mortality (62%) after 7–9 days. Cyclosporin A (CsA) was given at doses of 5, 2, and 0.5 mg per mouse, one or three times per week starting from Day 40 PI and continuing over the next 17 days. High serum levels of CsA were measured by radioimmunoassay. However, gross and microscopic pathological examination showed no indication of hepatic or renal toxicity at these doses. In the CsA-treated mice, there was a dose-dependent shortening of the length and severity of the attack forced by challenge with the third injection. The mortality was significantly ( P < 0.05) reduced when compared with the non-CsA-treated controls. In addition, the data demonstrate a decrease of lymphocyte-derived chemotactic factor produced from phytohemagglutinin-stimulated spleen cells of mice with chronic relapsing EAE treated with CsA when compared to normal mice and mice with chronic relapsing EAE treated with vehicle alone. We conclude that it is possible to effect an induced acute attack in ongoing chronic relapsing EAE with CsA treatment.

Prevention of experimental allergic encephalomyelitis (EAE) in the SJL/J mouse by whole body ultraviolet irradiation.

The cellular requirements for the in vivo induction of experimental allergic encephalomyelitis (EAE) were investigated in the SJL/J mouse. Exposure of mice to whole body ultraviolet (UV) irradiation, a treatment that has been shown in other systems to interfere selectively with antigen-presenting cell function, prevented the development of clinical and pathologic signs of acute EAE. Splenic T cells from UV-treated animals did not adoptively transfer resistance to EAE, making it unlikely that UV irradiation resulted in the generation of a specific suppressor cell population responsible for protection from EAE. UV irradiation was effective in preventing EAE when administered before initial immunization; UV irradiation was ineffective in modifying ongoing EAE or in preventing relapses of EAE induced by reimmunization. In additional experiments, adult thymectomized, lethally x-irradiated mice reconstituted with syngeneic marrow cells depleted of mature T lymphocytes were found to be resistant to the induction of EAE. Susceptibility was restored by the addition of splenic T cells, demonstrating that EAE induction is T cell-dependent in the mouse. The prevention of an experimental autoimmune demyelinating disease by whole body UV irradiation suggests that interference with the function of Ia-bearing accessory cells may represent an approach for immunotherapy in autoimmune disorders.

Failure of myelin basic protein to prevent or suppress experimental allergic encephalomyelitis in guinea pigs.

The encephalitogenic myelin basic protein (BP) was reported to be effective in preventing and suppressing the development of experimental allergic encephalomyelitis (EAE) when animals were treated before or after encephalitogenic challenge, respectively. In this report we show that pretreatment with 15 daily doses of 2.5 or 0.15 mg homologous BP (in IFA) failed to protect guinea pigs from subsequent challenge with encephalitogenic emulsion. Similarly, 15 daily injections of 1.0, 2.5, 5.0, or 10.0 mg guinea pig BP (in IFA) did not suppress development of or arrest ongoing EAE when the treatment was initiated on days 1, 4, 8, or 11 after an encephalitogenic challenge. The results show that over 50% of the treated animals developed hind leg paralysis (HLP), incontinence, or both, and the incidence of HLP was not altered significantly by a 10-fold increase in the amount of BP used for daily treatment. Further, all the treated and challenged animals developed histological lesions characteristic of disease. Treatment with BP delayed disease onset, prolonged the period of paralysis leading to recovery from HLP, and reduced both the prevelence of histological lesions as well as the incidence of death. It may be concluded that under these experimental conditions the administration of BP failed to protect from or suppress development of EAE.