Immunohistochemical localization of citrullinated proteins in adult rat brain

By using hybridoma technology, an IgM monoclonal antibody (F95) against multiple citrullinated synthetic and natural peptides was recently developed and used to stain immunohistochemically subsets of astrocytes and myelin basic protein (MBP) from selected regions of human brain (Nicholas and Whitaker [2002] Glia 37:328-336). With this antibody, the present study provides a more detailed localization of citrullinated epitopes in the central nervous system (CNS) by examining immunohistochemical staining patterns for F95 in the normal adult rat brain. Thus, immunohistochemical labeling for citrullinated epitopes was seen in white matter areas consistent with myelin staining; however, in general, it was more prominent and uniform in the caudal CNS (spinal cord, medulla oblongata, pons, and cerebellum) than in more rostral areas. F95 staining was also seen in cells and fibers often intimately associated with blood vessels and/or ventricular surfaces. By using dual-color immunofluorescence, the vast majority of this latter staining was colocalized within a subset of astrocytes also immunoreactive for glial fibrillary acidic protein (GFAP). By using Western blot analysis of rat brain proteins, multiple GFAP- and MBP-immunoreactive proteins and peptide fragments were seen, and many of them were also reactive with the F95 antibody. Thus, the present study not only demonstrates that citrullinated epitopes in normal rat brain are most concentrated in subsets of myelin and astrocytes but also provides evidence that GFAP, like MBP, may be present as multiple citrullinated isoforms.     

Increased citrullinated glial fibrillary acidic protein in secondary progressive multiple sclerosis

In this study, we demonstrate that grossly unaffected white matter from secondary progressive multiple sclerosis (SP-MS) patients is heavily citrullinated, as compared to normal white matter from control patients. Citrullination was most pronounced at plaque interfaces and was shown to colocalize with glial fibrillary acidic protein (GFAP)-immunoreactivity using dual color immunofluorescence. In contrast, the plaques themselves weakly stained for citrullinated proteins compared to control white matter and usually contained a blood vessel with surrounding astrocytes that were positive both for citrullinated proteins and GFAP. In SP-MS brain samples, but not in normal brains, long fibers of colocalized GFAP- and citrullinated proteins extended into the gray matter. Increased numbers of astrocytes containing citrullinated proteins and GFAP were also present at the junction between the gray and white matter in SP-MS brains. Western blot analysis of acidic brain proteins from nonplaque-containing white matter showed upregulation of multiple citrullinated GFAP proteins in SP-MS brains as compared to controls. Our results demonstrate that increased amounts of citrullinated GFAP are present in SP-MS brains, but also shows that these proteins are present in areas of MS brains that were grossly normal appearing. These data raise the possibility that citrullination of GFAP contributes to the pathophysiology of MS.     

Citrullination of central nervous system proteins during the development of experimental autoimmune encephalomyelitis

Immunization of mammals with central nervous system (CNS)-derived proteins or peptides induces experimental autoimmune encephalomyelitis (EAE), a disease resembling the human autoimmune disease multiple sclerosis (MS). Both diseases are accompanied by destruction of a part of the of the myelin sheaths, which surround neurites in the CNS. Previous studies in MS have described alterations in the citrullination of myelin basic protein, one of the main protein constituents of the myelin sheath. Here, we show that, also during the development of EAE in mice, hypercitrullination occurs in the areas of the spinal cord that show the highest degree of inflammation and that myelin basic protein and glial fibrillary acidic protein are among the hypercitrullinated proteins. We conclude that hypercitrullination of myelin proteins in the CNS is a common phenomenon in demyelinating disease. Hypercitrullination may cause conformational changes in proteins, so the affected proteins may be involved in the pathogenesis of CNS autoimmune disease by acting as autoreactive T-cell epitopes. This is the first report in which hypercitrullination of CNS proteins in EAE is described and in which proteins other than myelin basic protein are reported to be citrullinated during autoimmune-mediated CNS inflammation.     

Experimental autoimmune encephalomyelitis induction in peptidylarginine deiminase 2 knockout mice

During the development of multiple sclerosis the destruction of the myelin sheath surrounding the neurites is accompanied by citrullination of several central nervous system (CNS) proteins, including myelin basic protein and glial fibrillary acidic protein. In experimental autoimmune encephalomyelitis (EAE), a disease induced in animals by immunization with proteins or peptides from the CNS, the animals develop symptoms similar to multiple sclerosis (MS). The increased levels of citrullinated CNS proteins associated with MS are also observed during the development of EAE. To study the role of CNS protein citrullination in EAE development, we induced EAE with a peptide derived from myelin oligodendrocyte glycoprotein (MOG(35-55)) in mice lacking the peptidylarginine deiminase 2 (PAD2) protein, because this enzyme was the most likely candidate to be involved in catalyzing CNS protein citrullination in the diseased state. Even though the PAD2 knockout mice displayed a dramatic reduction in the amount of citrullination present in the CNS, indicating that PAD2 is indeed responsible for the majority of detectable citrullination observed in EAE, the development of EAE was not impaired by genetic deletion of PAD2, suggesting that PAD2 catalyzed citrullination is not essential to the development of EAE.     

Preparation of a monoclonal antibody to citrullinated epitopes: its characterization and some applications to immunohistochemistry in human brain

Using hybridoma technology, an IgM monoclonal antibody (mAb), designated as F95, was developed against a deca-citrullinated peptide (DCP) consisting of 10 citrulline residues and a carboxyl Gly-Gly-Cys through which DCP was covalently linked to an activated carrier protein, keyhole limpet hemocyanin (KLH). Clones were selected on the basis of not reacting with human unmodified and noncitrullinated myelin basic protein (MBP), MBP-C1, but reacting well with human citrullinated MBP (MBP-C8). When tested by ELISA, this mAb demonstrated minimal reactivity with human MBP-C1, varying reactivity with the C2-C5 isomers of human MBP, moderate binding with guinea pig MBP-C8, and strong reactivity with human MBP-C8. By ELISA, mAb F95 was directed predominantly against citrulline, not MBP, as revealed by its binding to DCP linked with activated KLH, bovine serum albumin (BSA), or ovalbumin (OA), but not with KLH, BSA, or OA alone. Immunohistochemistry of normal human brain demonstrated that F95 stained central nervous system myelin and a subset of astrocytes. Given the citrulline-directed features of mAb F95, this immunohistochemical pattern suggests that certain astroglial filaments expressing glial fibrillary acidic protein also contain citrulline-bearing components. These potentially implicate citrullinated proteins, notably in astroglial filaments, in a variety of normal and pathological neurobiological processes.     

Oligoclonal IgG bands synthesized in the central nervous system are present in rats with experimental autoimmune encephalomyelitis

OBJECTIVE: Oligoclonal bands (OBs) in electrophoresis of cerebrospinal fluid (CSF) are present in multiple sclerosis and here is investigated whether these also occur in experimental autoimmune encephalomyelitis (EAE). MATERIAL AND METHODS: Experimental autoimmune encephalomyelitis was induced in 42 DA rats after immunization with rat spinal chord homogenate and the occurrence of OBs were detected by electrophoresis of both sera and CSF. The relationship between disease symptoms, antibody response against myelin basic protein (MBP), myelin oligodendrocyte glycoprotein (MOG) and appearance of OBs was studied. RESULTS: Development of CSF-specific OB was found to occur, 6 weeks after immunization, in seven of 42 rats. OB was detected in rats with an antibody response against MBP, whereas as a role no such bands were present in rats with an antibody response against MOG. Initially severe disease symptoms were correlated to a concomitant intense oligoclonal antibody response. CONCLUSION: Cerebrospinal fluid-specific OB occurs in EAE. It is present in rats with an anti-MBP, but not in rats with an anti-MOG antibody response. A severe disease results in an intense oligoclonal antibody response, which might have an anti-inflammatory effect.     

Generation of autonomously pathogenic neo-autoreactive TH1 cells during the development of the determinant spreading cascade in murine autoimmune encephalomyelitis

Chronic progression of autoimmune disease is accompanied by the acquisition of autoreactivity to new self-determinants. Recent evidence indicates that this process, commonly referred to as determinant spreading, may be pathogenic for chronicity. Our studies on experimental autoimmune encephalomyelitis (EAE), a murine model widely used in multiple sclerosis (MS) studies, have shown that determinant spreading develops as a predictable sequential cascade of neo-autoimmunity during progression to chronic disease. By 7–8 weeks after immunization of (SWRxSJL)F₁ mice with the immunodominant myelin proteolipid protein determinant (PLP 139–151), splenocytes consistently respond to the immunodominant myelin basic protein determinant (MBP 87–99). In the present study, we directly address the pathogenicity of neo-autoimmunity resulting from endogenous self-priming during the course of disease. Our results indicate that T cells responding to the spreading MBP 87–99 determinant produce a proinflammatory cytokine profile consistent with type 1 helper T cells (Th1) cells. In addition, splenocytes activated to the spreading MBP 87–99 determinant consistently transfer acute EAE in naive recipients even when T cells reactive to the priming PLP 139–151 immunogen are eliminated by bromodeoxyuridine (BUdR)-mediated photolysis. Our data indicate that endogenous neo-autoantigen priming during chronic autoimmune disease generates type 1 helper T cells (Th1) cells that are autonomously pathogenic. These results provide further evidence supporting the view that determinant spreading is a pathogenic process that leads to chronic progression of autoimmune disease. © 1996 Wiley-Liss, Inc.     

Effect of Theiler's murine encephalomyelitis virus and cytokines on cultured oligodendrocytes and astrocytes

The pathogenesis of Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is still controversial. Our hypothesis is that primary infection of oligodendrocytes (OLGs) is not a crucial event in the pathogenesis of demyelination in this model. In fact, it has been proposed that myelin may be destroyed, as an innocent bystander, following an antiviral delayed-type hypersensitivity (DTH) response. This hypothesis would not need widespread oligodendroglial infection, because virus present in other cells would be sufficient to trigger a DTH response. The present study demonstrates that cultured OLGs and astrocytes from susceptible strains of mice (SJL and DBA) and immortalized OLGs can be infected with TMEV in vitro. Infection of OLGs, however, is at very low levels and does not result in overt cytolytic effect. In contrast, infection of immortalized OLGs is very efficient and results in clear cytolysis. Because an important characteristic of DTH responses is the liberation of potentially injurious cytokines into adjacent tissues, we also examined the effects of mouse recombinant tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), and interferon-γ (IFN-γ) on cultured OLGs and immortalized OLGs. We found that TNF-α caused immortalized. OLG cytotoxicity in a time- and dose-dependent manner. In contrast, no cytotoxicity was observed on primary OLGs with any of the above cytokines. To determine whether functional effects could be demonstrated on primary OLGs by either virus or cytokines, we measured mRNA expression of different myelin proteins in primary and immortalized OLGs exposed to virus or TNF-α. Neither the BeAn strain or the GDVII strain of TMEV interfered with myelin protein mRNA expression in primary OLGs, whereas GDVII virus dramatically reduced myelin OLG glycoprotein (MOG) mRNA in immortalized OLGs. Interestingly, although even high concentrations of TNF-α (10,000 U/ml) did not produce primary OLG cytotoxicity, they resulted in a significant reduction in mRNA for both myelin basic protein (MBP) and MOG in these cells. TNF-α (at 500 U/ml) also specifically reduced MOG mRNA in immortalized OLGs. Because immortalized OLGs are considered to be arrested at an early stage of maturation, our results suggest that immature OLGs are susceptible to both virus- and cytokine-dependent cytotoxicity whereas mature OLGs are resistant to cytolysis by either TMEV or cytokines. TNF-α however, is capable of reducing mRNA expression of myelin proteins in primary OLGs; therefore, it may participate in the induction of demyelination, as suggested by the DTH-mediated hyphotesis. © 1996 Wiley-Liss, Inc.     

Expression of the HGF receptor c‐met by macrophages in experimental autoimmune encephalomyelitis

Hepatocyte growth factor (HGF) is a pleiotropic cytokine able to evoke a wide array of cellular responses including proliferation, migration, and survival through activation of its receptor c‐met. Various types of leukocytes have been described to express c‐met suggesting that HGF/c‐met signaling may directly influence leukocyte responses in inflammation. We have investigated the HGF/c‐met pathway in experimental autoimmune encephalomyelitis (EAE), a common mouse model of multiple sclerosis (MS), in which macrophages play a dual role, contributing directly to CNS damage at disease onset but promoting recovery during remission by removing myelin debris. Here we show that during EAE both HGF and c‐met are expressed in the CNS and that c‐met is activated. We subsequently demonstrate that c‐met is primarily expressed in inflammatory lesions by macrophages and a small number of dendritic cells (DCs) and oligodendrocyte progenitor cells (OPCs) but not by microglia or T cells. Complementary in vitro experiments show that only LPS and TNFα, but not IL‐6, IL‐10, or IL‐13, are able to induce c‐met expression in macrophages. In addition, using TNF signaling deficient macrophages we demonstrate that LPS and TNFα induce c‐met through distinct pathways. Furthermore, TNFα‐ and LPS‐induced c‐met is functional because treatment of macrophages with recombinant HGF results in rapid phosphorylation of c‐met. Interestingly, HGF/c‐met signaling does not modulate cytokine expression, phagocytosis, or antigen presentation but promotes proliferation of activated macrophages. Taken together, our data indicate a pro‐inflammatory role for the HGF/c‐met pathway in EAE rather than a role in the initiation of repair mechanisms. © 2009 Wiley‐Liss, Inc.     

Immunocytochemical staining for glial fibrillary acidic protein and the metabolism of cytoskeletal proteins in experimental allergic encephalomyelitis

Spinal cord sections from Lewis rats with acute experimental allergic encephalomyelitis (EAE) showed greatly increased staining of astrocytes when stained immunocytochemically for glial fibrillary acidicc protein (GFAP). Fibrous processes in white matter were heavily stained early in the course of the disease when paralysis was first evident (10–12 days after injection of guinea pig spinal cord myelin), then protoplasmic astrocytes were stained in the gray matter and became more heavily stained at 20 dats post-injection. The stained astrocytes were evenly distributed throughout the tissue, and did not correspond to the sites of the lesions. Spinal cord slices of control and EAE rats were incubated with [³H]amino acids, then cytoskeletal proteins were prepared in an enriched fraction, separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the protein bands counted for radioactivity. In the EAE rat all cytoskeletal proteins, including the neurofilaments, vimentin, microtubules, GFAP and actin, showed increased uptake of radioactive amino acids. Immunoprecipitation of GFAP with specific antiserum showed increased radioactivity in the complex beginning at day 10 when cellular infiltration was beginning in the EAE animals. As the disease became acute, the radioactivity in the immunoprecipitated GFAP increased, in some cases to very high levels, then by day 18 when recovery was underway, the radioactivity had fallen to normal levels. Possible agents causing metabolic activation of protein synthesis in EAE animals include stimulating substances elaborated by infiltrating lymphoid scells, and the generalized edema accompanying the demyelinative condition. The activation of GFAP protein staining and metabolism in EAE might serve as a model for the activated growth of astrocyte processes which cause the severe gliosis seen in multiple sclerosis.     

Murine complement C4 is not required for experimental autoimmune encephalomyelitis

In vitro studies have demonstrated that myelin and myelin-derived proteins activate both the classical and alternative complement pathways. More recently, studies have shown that mice deficient in factor B, a protein required for activation of the alternative pathway, have attenuated experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. The relative contribution of the classical pathway to the pathogenesis of EAE has remained unexplored. To address this question, we performed EAE using mice deficient in C4 (C4-/-), a protein required for full activation of the classical pathway. We found that deletion of the C4 gene does not significantly change either the time of onset or the severity and tempo of myelin oligodendrocyte-induced EAE compared with controls with a fully intact complement system. We observed similar levels of cellular infiltration (CD11b+ macrophages and CD3+ T cells) and demyelination in the two kinds of mice. Despite this, ribonuclease protection assays demonstrated a two- to fourfold increase in several pro-inflammatory cytokines in C4-/- mice with EAE, including interleukin-beta (IL-1beta), IL-18, tumor necrosis factor-alpha (TNF-alpha), IP-10, and RANTES. These results support the conclusion that the contribution of murine complement to the pathogenesis of demyelinating disease is realized via the alternative pathway.     

IL-10 fails to abrogate experimental autoimmune encephalomyelitis

Mice adoptively-sensitized to develop chronic relapsing experimental autoimmune encephalomyelitis (EAE), a model for the human demyelinating condition, multiple sclerosis (MS), were given injections of recombinant human IL-10 at various timepoints post-sensitization in an attempt to abrogate disease development. IL-10 is a Th2 immunomodulatory cytokine with known down-regulatory effects upon Th1 responses and macrophages. Contrary to a previous report on EAE and the predicted outcome, after repeated experiments, IL-10 was found to elicit a worsening or no effect upon EAE in the mouse. Animals were studied clinically, histopathologically and immunocytochemically. On no occasion was disease ameliorated by IL-10. Pretreatment with IL-10 of lymph node cells used to transfer EAE had no effect upon disease outcome, indicating that the cells were already committed effectors. Administration of anti-IL-10 monoclonal antibody before onset of signs had no effect when given early post-sensitization and caused marked worsening when given immediately before onset of signs. In the context of this autoimmune demyelinating model, these results suggest that IL-10 alone is insufficient to reverse the effector response and indeed may serve to enhance the cascade of events in EAE. © 1996 Wiley-Liss, Inc.     

Restoration of conduction in the spinal roots correlates with clinical recovery from experimental autoimmune encephalomyelitis

In the Lewis rat, acute experimental autoimmune encephalomyelitis (EAE) induced by inoculation with myelin basic protein (MBP) and adjuvants is characterized by tail and hindlimb weakness that resolves spontaneously after several days. In rats with neurological signs of this form of EAE (MBP-EAE) we have previously demonstrated demyelination and nerve conduction block in the proximal peripheral nervous system (PNS) and in the central nervous system (CNS). The present study was performed to assess conduction in the PNS and CNS, after recovery from acute MBP-EAE, using direct recordings from surgically exposed spinal roots and spinal cord dorsal columns. The study revealed that 1–2 weeks after clinical recovery from tail paralysis there was almost complete restoration of conduction in the sacral spinal roots but persistent severe conduction abnormalities in the dorsal columns. Significant restoration of conduction through the dorsal columns occurred over the following 2 weeks. These findings indicate that PNS conduction block due to a demyelinating polyradiculitis is a major cause of the neurological signs of acute MBP-EAE in the Lewis rat.© 1995 John Wiley & Sons, Inc.     

Quantitation of myelin oligodendrocyte glycoprotein and myelin basic protein in the thymus and central nervous system and its relationship to the clinicopathologic features of autoimmune encephalomyelitis

There is controversy whether the amount of autoantigens expressed in the thymus regulates negative selection of autoreactive T cells and determine susceptibility or resistance to experimental autoimmune encephalomyelitis (EAE). In the present study, we have addressed this issue by quantifying neuroantigens in the thymus of two EAE-susceptible (LEW and LEW.1AV1) and one EAE-resistant (BN) rat strains. We further examined whether amounts of neuroantigens in various parts of the central nervous system (CNS) affect the clinical course and lesion distribution of acute and chronic EAE. Real-time PCR and histologic analyses showed that there was no significant difference in the amount and distribution of myelin oligodendrocyte glycoprotein and myelin basic protein in the thymus and CNS among the three strains and that both acute and chronic EAE lesions in the CNS were preferentially distributed in the area where neuroantigens were abundantly present. These findings suggest that susceptibility or resistance to EAE is not regulated by the amount of the neuroantigens expressed in the thymus. Furthermore, the lesion distribution, but not the clinical course, of EAE is related to the neuroantigen expression in the CNS.     

Prevention of experimental allergic encephalomyelitis by ganglioside GM4

Guinea pigs inoculated with a mixture of myelin basic protein and the myelin-specific ganglioside, sialosylgalactosylceramide (G_M4), do not develop the signs or neuropathology of experimental allergic encephalomyelitis. The results indicate that G_M4 cloaks the basic protein molecule so that it is no longer immunopathogenic in these animals. The interaction of basic protein with G_M4, previously shown in vitro, appears to be relevant to the pathogenesis of experimental allergic encephalomyelitis in guinea pigs.     

髓鞘少突胶质细胞糖蛋白抗体在多发性硬化中的意义

目的探讨髓鞘少突胶质细胞糖蛋白(MOG)抗体与多发性硬化(MS)临床表现及复发缓解型MS(RRMS)复发的关系。方法采用酶联免疫吸附法(ELISA)对60例MS、23例其他炎性神经疾病(OIND)、29例非炎性神经疾病(NIND)以及50例神经系统正常的对照(NC)患者血清及脑脊液(CSF)MOG抗体进行检测。结果MS患者CSFMOG抗体阳性率为28.3%(17/60),明显高于NC组[2%(1/50)]和NIND组[0%(0/29)],但与OIND组[21.7%(5/23)]比较差异无统计学意义。各组血清MOG抗体均为阴性。抗体阳性率急性活动期为31.8%(14/44),与稳定期[18.75%(3/16)]比较差异无统计学意义。CSFMOG抗体阳性的RRMS患者复发时间早于阴性患者,且其第1、2年复发率均高于阴性患者。结论在部分MS患者中枢神经系统内存在异常的MOG特异性B细胞免疫应答,且CSFMOG抗体对RRMS的复发有一定预测作用。     

Evaluation of diagnostic criteria and red flags of myelin oligodendrocyte glycoprotein encephalomyelitis in a clinical routine cohort

AimsMyelin oligodendrocyte glycoprotein antibodies (MOG‐IgG) have been proposed to define “MOG encephalomyelitis” (MOG‐EM), with published diagnostic and “red flag” criteria. We aimed to evaluate these criteria in a routine clinical setting.MethodsWe retrospectively analyzed patients with borderline/positive MOG‐IgG and applied the diagnostic and red flag criteria to determine likelihood of MOG‐EM diagnosis. Para‐/clinical parameters were described and analyzed with chi‐square test.ResultsIn total, 37 patients fulfilled MOG‐EM diagnostic criteria (female‐to‐male ratio: 1.6:1, median onset age: 28.0 years [IQR 18.5‐40.5], n = 8 with pediatric onset). In 24/37, red flags were present, predominantly MOG‐IgG at assay cutoff and/or MRI lesions suggestive of multiple sclerosis (MS). As proposed in the consensus criteria, these patients should rather be described as “possible” MOG‐EM. Of these, we classified 13 patients as “unlikely” MOG‐EM in the presence of the red flag “borderline MOG‐IgG” with negative MOG‐IgG retest or coincidence of ≥1 additional red flag. This group mainly consisted of patients diagnosed with MS (n = 11). Frequency of cerebrospinal fluid (CSF‐)—specific oligoclonal bands (OCB) is significantly lower in definite vs possible and unlikely MOG‐EM (P = .0005).ConclusionEvaluation of diagnostic and red flag criteria, MOG‐IgG retesting (incl. change of assay), and CSF‐specific OCB are relevant in clinical routine cohorts to differentiate MOG‐EM from MS.     

Myelination by transplanted fetal and neonatal oligodendrocytes in a dysmyelinating mutant

Demyelination is a major feature of CNS injury and disease, including multiple sclerosis. To examine the potential for myelination by transplanted oligodendrocytes, initially described by Gumpel et al., we have transplanted neonatal cortex of mice with normal myelin into a dysmyelinating mutant, the shiverer mouse. We have found that oligodendrocyte precursors mature and synthesize myelin following transplantation. Immunostaining with antibodies to myelin basic protein (MBP), neurofilament protein and glial fibrillary acidic protein, demonstrates myelination both within the graft and extending out into the host, axonal sprouting from the graft which parallels the MBP-reactivity, and minimal astrocytic proliferation in response to the transplant.     

Analysis of gene expression in MOG-induced experimental autoimmune encephalomyelitis after treatment with a novel brain-penetrating antioxidant

Accumulating data from experimental studies indicate that oxidative stress has a major role in the pathogenesis of multiple sclerosis (MS). It has been suggested that local production of reactive oxygen species, probably by macrophages, mediates axonal damage in both MS patients and the mouse model experimental autoimmune encephalomyelitis (EAE). We have shown previously that our novel brain-penetrating antioxidant, N-acetylcysteine amide (AD4), reduces the clinical and pathological symptoms, including inflammation and axonal damage in myelin oligodendrocyte glycoprotein (MOG)-induced chronic EAE in mice. The aim of this study was to examine the molecular mechanism by which AD4 exerts protection in MOG-induced EAE mice. Therefore, we analyzed gene-expression profile in the spinal cords of MOG-induced chronic EAE mice and compared them with MOG-induced mice treated with AD4, using a cDNA microarray. We found that MOG treatment up-regulated genes encoding growth factors, cytokines, death receptors, proteases, and myelin structure proteins, whereas MOG- and AD4-treated mice demonstrated gene expression profiles similar to that seen in na?ve healthy mice. In conclusion, our study shows that chronic AD4 administration suppresses the induction of various pathological pathways that play a role in EAE and probably in MS.