Critical role of antigen-specific antibody in experimental autoimmune encephalomyelitis induced by recombinant myelin oligodendrocyte glycoprotein

The role of B cells and antibody in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) remains controversial. We previously demonstrated that B cells are required for EAE to be induced by the 120-amino acid extracellular domain of myelin oligodendrocyte glycoprotein (MOG). In the present study, the role of B cells in MOG-induced EAE was further characterized. Passive transfer of activated B cells or serum from MOG-primed wild-type (WT) mice was found to reconstitute the ability for clinical and histological EAE to be induced in MOG-immunized B cell-deficient mice. MOG-induced EAE did not occur with transfer of B cells that had been nonspecifically activated by lipopolysaccharide or isolated from na?ve or myelin basic protein (MBP)-primed WT mice. Likewise, MOG-primed serum, but not naive serum or serum from MBP-, Hen egg lysozyme-, or MOG(35-55)-primed mice, led to EAE in B cell-/- animals. While both MOG-primed B cells and serum reconstituted the ability for disease induction, MOG-primed serum was much more efficient, leading to clinical and histological EAE similar to that seen in the WT. Injection of MOG serum into healthy B cell-/- mice 30 days after MOG immunization led to rapid appearance of clinical signs and CNS inflammation, indicating that an antigen-specific factor is necessary for initiation of CNS inflammation,and not just demyelination. These data strongly suggest that MOG-specific antibody is critical to the initiation of MOG-induced murine EAE.     

Novel pathogenic epitopes of myelin oligodendrocyte glycoprotein induce experimental autoimmune encephalomyelitis in C57BL/6 mice

Myelin oligodendrocyte glycoprotein (MOG), a minor protein of the central nervous system myelin, is recognized as a potential target in multiple sclerosis and neuromyelitis optica. The extracellular domain of MOG is commonly used in a wide range of mouse strains and other animals to induce experimental autoimmune encephalomyelitis (EAE), an autoimmune animal model of multiple sclerosis, because it is a target for antibody‐mediated attack. Previous studies, using selected peptides, have indicated that MOG^35–55 peptide is an encephalitogenic epitope in C57BL/6 (H‐2^b) mice. A more systematic analysis of both T‐cell and B‐cell responses following immunization of C57BL/6 mice with either recombinant extracellular mouse MOG protein (1–116) or with overlapping peptides spanning the whole sequence of MOG, before assessment of responses to 15 mer and 23 mer peptides was undertaken. The studies identified T‐cell responses within the MOG^35–55 (extracellular domain) but also two new immunogenic and encephalitogenic T‐cell epitopes within residues MOG^113–127, MOG^120–134 (localized in the transmembrane region) and MOG^183–197 (in the second hydrophobic MOG domain). In addition, residue MOG^113–127 was found to be a B‐cell epitope, suggesting that this may be a useful adjunct for the induction of EAE as well as for immunological studies in C57BL/6 mice, which are increasingly being used to study immune function through the use of transgenic and gene knockout technology.     

Antibodies to myelin oligodendrocyte glycoprotein are not involved in the severity of chronic non-remitting experimental autoimmune encephalomyelitis

To elucidate the role of antibodies in development of chronic non-remitting experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice, which is a well-established Th1-mediated autoimmune disease, and the involvement of activation-induced cytidine deaminase (AID) in Th1-mediated function, we have investigated the myelin oligodendrocyte glycoprotein (MOG)-induced EAE in mice deficient of AID, which is absolutely required for class switching and somatic hypermutation. Following immunization with MOG, AID(-/-) had completely same levels of clinical and pathological severity of EAE when compared with AID(+/-) and AID(+/+), although AID(-/-) did not produce IgG and anti-MOG IgG. Similar levels of T cell proliferation and a modest increase of anti-MOG IgM synthesis were found in spleen cells of AID(-/-) stimulated with MOG. These results indicate that antibodies are not involved in development of EAE in C57BL/6 mice.     

IL-6-deficient mice are resistant to the induction of experimental autoimmune encephalomyelitis provoked by myelin oligodendrocyte glycoprotein

The role of IL-6 in experimental autoimmune encephalomyelitis (EAE) provoked by myelin oligodendrocyte glycoprotein (MOG) was investigated using IL-6-deficient mice. We show here that IL-6-deficient mice were resistant to the MOG-induced EAE as compared to wild-type mice (one out of 18 versus 17 out of 20). The delayed-type hypersensitivity response, lymphocyte proliferation response and antibody reactivity to MOG in IL- 6-deficient mice were significantly lower than those in wild-type mice. Furthermore, the histological examination revealed that no infiltration of inflammatory cells was observed in the central nervous system of IL- 6-deficient mice. These results indicate that IL-6 may play a crucial role in the induction phase of EAE. Given the potential relevance of this animal model for multiple sclerosis (MS), it is possible that anti- IL-6 therapy may be useful in the prevention of relapses of MS.      

T cell epitope spreading to myelin oligodendrocyte glycoprotein in HLA-DR4 transgenic mice during experimental autoimmune encephalomyelitis

Epitope spreading has been implicated in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and human multiple sclerosis (MS). T cell epitope spreading has been demonstrated in rodents for myelin basic protein (MBP) and proteolipid protein (PLP) determinants, but not for myelin oligodendrocyte glycoprotein (MOG), another important myelin antigen. Moreover, the role of human autoimmunity-associated MHC molecules in epitope spreading, including HLA-DR2 and DR4, has not been formally examined. To address these questions, we investigated epitope spreading to MOG determinants in HLA-DR4 (DRB1*0401) transgenic mice during EAE. The data show that upon induction of EAE in HLA-DR4 transgenic mice with the immunodominant HLA-DR4-restricted MOG peptide 97-108 (MOG(97-108); TCFFRDHSYQEE), the T cell response diversifies over time to MOG(181-200) (core: MOG(183-191); FVIVPVLGP) and MBP. The spreading epitope MOG(181-200) binds with high affinity to HLA-DRB1*0401 and is presented by human HLA-DRB1*0401+antigen presenting cells. Moreover, this epitope is encephalitogenic in HLA-DRB1*0401 transgenic mice. This study demonstrates intra- and intermolecular epitope spreading to MOG and MBP in "humanized" HLA-DR4 transgenic mice.     

Myelin oligodendrocyte glycoprotein-DNA vaccination induces antibody-mediated autoaggression in experimental autoimmune encephalomyelitis

One strategy to reestablish self tolerance in autoimmune diseases is based on the use of DNA vaccination to induce ectopic expression of the target autoantigen. We assessed the potential of vaccination with a DNA construct encoding the myelin oligodendrocyte glycoprotein (MOG), an important candidate autoantigen in multiple sclerosis, to induce tolerance and protect against experimental autoimmune encephalomyelitis (EAE). Unexpectedly, mice vaccinated with MOG-DNA developed an exacerbated form of EAE when challenged with either MOG or an unrelated encephalitogen, myelin proteolipid protein. We demonstrate that this is due to the inability of DNA vaccination to tolerize the MOG-specific T cell response and to the concomitant induction of a cytopathic MOG-specific autoantibody response, which is pathogenic, enhancing demyelination, inflammation and disease severity. Our data suggest that tolerogenic strategies for autoimmune diseases based on DNA vaccination should be approached with caution, as the outcome is unpredictable.     

Vaccination with myelin oligodendrocyte glycoprotein adsorbed to alum effectively protects DBA/1 mice from experimental autoimmune encephalomyelitis

To prevent an organism from developing autoimmunity the body limits the number of autoreactive cells through thymic negative selection and regulates their activity through induction of suppressor T cells. Development of antigen-specific therapies provides an interesting opportunity to imitate the body's own, often effective, method of protection. Our study demonstrates that DBA/1 mice could be protected from experimental autoimmune encephalomyelitis induced through injection of recombinant myelin oligodendrocyte glycoprotein (rMOG) when they were previously immunized intraperitoneally with rMOG adsorbed to aluminium hydroxide. This protection was associated with a decreased IFN-gamma production by rMOG-specific cells, but not a decreased proliferative response. Protection was long lasting, indicating that MOG-alum vaccination might be developed as a prophylactic therapy in multiple sclerosis.     

Gender does not influence the susceptibility of C57BL/6 mice to develop chronic experimental autoimmune encephalomyelitis induced by myelin oligodendrocyte glycoprotein

Multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS), is more prevalent in females than males. It is well documented that a significant gender difference exits in the susceptibility of mice to develop experimental autoimmune encephalomyelitis (EAE), a model of MS, induced by myelin basic protein or proteolipid protein. In contrast, we report here that no significant difference between female mice and male mice with myelin oligodendrocyte glycoprotein (MOG)-induced EAE was observed in the incidence of disease, clinical course, histological findings in the CNS, T cell response and cytokine production of spleen cells to MOG, and anti-MOG IgG level in serum. These results suggest that gender-related difference in EAE depends on the encephalitogen and/or the strain of animals used. Given that MOG is a putative pathogenic myelin antigen in MS, the present findings may have implications for the pathogenesis of this disease.     

Methylprednisolone induces reversible clinical and pathological remission and loss of lymphocyte reactivity to myelin oligodendrocyte glycoprotein in experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is an animal model of human multiple sclerosis (MS). EAE, induced by immunisation with myelin-associated autoantigens, is characterised by an inflammatory infiltrate in the central nervous system (CNS) associated with axonal degeneration, demyelination and damage. We have recently shown in an experimental mouse model of autoimmune gastritis that methylprednisolone treatment induces a reversible remission of gastritis with regeneration of the gastric mucosa. Here, we examined the effect of oral methylprednisolone on the mouse EAE model of human MS induced by immunisation with myelin oligodendrocyte glycoprotein peptide (MOG_35–55). We examined the clinical scores, CNS pathology and lymphocyte reactivity to MOG_35–55 following treatment and withdrawal of the steroid. Methylprednisolone remitted the clinical signs of EAE and the inflammatory infiltrate in the CNS, accompanied by loss of lymphocyte reactivity to MOG_35–55 peptide. Methylprednisolone withdrawal initiated relapse of the clinical features, a return of the CNS inflammatory infiltrate and lymphocyte reactivity to MOG_35–55 peptide. This is the first study to show that methylprednisolone induced a reversible remission in the clinical and pathological features of EAE in mice accompanied by loss of lymphocyte reactivity to the encephalitogen. This model will be useful for studies directed at a better understanding of mechanisms associated with steroid-induced disease remission, relapse and remyelination and also as an essential adjunct to an overall curative strategy.     

Methylprednisolone induces reversible clinical and pathological remission and loss of lymphocyte reactivity to myelin oligodendrocyte glycoprotein in experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is an animal model of human multiple sclerosis (MS). EAE, induced by immunisation with myelin-associated autoantigens, is characterised by an inflammatory infiltrate in the central nervous system (CNS) associated with axonal degeneration, demyelination and damage. We have recently shown in an experimental mouse model of autoimmune gastritis that methylprednisolone treatment induces a reversible remission of gastritis with regeneration of the gastric mucosa. Here, we examined the effect of oral methylprednisolone on the mouse EAE model of human MS induced by immunisation with myelin oligodendrocyte glycoprotein peptide (MOG(35-55)). We examined the clinical scores, CNS pathology and lymphocyte reactivity to MOG(35-55) following treatment and withdrawal of the steroid. Methylprednisolone remitted the clinical signs of EAE and the inflammatory infiltrate in the CNS, accompanied by loss of lymphocyte reactivity to MOG(35-55) peptide. Methylprednisolone withdrawal initiated relapse of the clinical features, a return of the CNS inflammatory infiltrate and lymphocyte reactivity to MOG(35-55) peptide. This is the first study to show that methylprednisolone induced a reversible remission in the clinical and pathological features of EAE in mice accompanied by loss of lymphocyte reactivity to the encephalitogen. This model will be useful for studies directed at a better understanding of mechanisms associated with steroid-induced disease remission, relapse and remyelination and also as an essential adjunct to an overall curative strategy.     

地塞米松对实验性自身免疫性脑脊髓炎小鼠髓鞘保护作用的研究

目的:分析地塞米松对实验性自身免疫性脑脊髓炎(EAE)小鼠炎症反应、髓鞘脱失及髓鞘再生的影响,探讨地塞米松治疗多发性硬化的新作用。方法:应用MOG35-55免疫C57BL/6小鼠建立EAE模型。小鼠随机分为正常对照组、EAE组及地塞米松组,观察各组临床症状;采用HE染色、LFB染色、透射电镜扫描及免疫组化染色方法,检测免疫后第13、20、30 d各组小鼠脊髓组织炎症反应、髓鞘脱失及髓鞘再生情况。结果:地塞米松显著降低EAE小鼠发病率、延缓起病时间、减轻疾病严重程度。各个时间点地塞米松组脊髓组织炎性细胞浸润、髓鞘脱失及轴索变性程度较EAE组明显减轻。免疫后第20、30 d,EAE组Olig2阳性细胞数较正常对照组明显增加;免疫后各时间点,地塞米松组Olig2阳性细胞数较正常对照组均明显增加,第13、20 d较EAE组明显增加。结论:地塞米松可增加脊髓组织Olig2表达、促进髓鞘再生,这可能为地塞米松治疗EAE及多发性硬化的效应途径。     

Decreased severity of myelin oligodendrocyte glycoprotein peptide 33 - 35-induced experimental autoimmune encephalomyelitis in mice with a disrupted TCR delta chain gene

Immunization of C57BL / 6 mice with myelin oligodendrocyte glycoprotein (MOG) peptide (p) 35 - 55 induces chronic experimental autoimmune encephalomyelitis (EAE). The role of gamma delta T cells in the regulation of EAE is unclear. We investigated gamma delta T cells in C57BL / 6 wild-type mice and C57BL / mice with a disrupted TCRdelta chain gene (delta(- / -) mice) using MOG p35 - 55. We found significantly less disease in delta(- / -) mice immunized with MOG / complete Freund's adjuvant (mean maximal EAE score 4.3 +/- 0.8 in wild-type vs. 2.3 +/- 0.5 in delta(- / -) mice). Transfer of wild-type spleen cells restored the ability of delta(- / -) mice to develop equally severe EAE as wild-type mice. In addition to IFN-gamma, IL-2, IL-5 and IL-10 was decreased in delta(- / -) mice. Decreased immune responses were also seen in delta(- / -) animals immunized with OVA peptide or protein and in concanavalin A-stimulated splenocytes from delta(- / -) mice. Enriched dendritic cells from delta(- / -) mice secreted significantly less TNF-alpha in response to lipopolysaccharide stimulation. Furthermore, when EAE was induced by adoptive transfer of an anti-MOG p35 - 55 alpha beta T cell line, there was a striking reduction of disease incidence (0 %) and severity in delta(- / -) as compared to wild-type mice (83 % incidence). delta(- / -) mice showed no cellular infiltration in the spinal cord whereas wild-type animals had infiltration of macrophages, B cells, alpha beta- and gamma delta T cells. In adoptive transfer EAE, there was reduced IL-2 and IFN-gamma secretion in delta(- / -) mice. These results demonstrate an impaired immune response in the delta(- / -) mouse that is associated with a defect in developing both actively induced and adoptively transferred EAE.     

Immune modulation by a tolerogenic myelin oligodendrocyte glycoprotein (MOG)10–60 containing fusion protein in the marmoset experimental autoimmune encephalomyelitis model

Current therapies for multiple sclerosis (MS), a chronic autoimmune neuroinflammatory disease, mostly target general cell populations or immune molecules, which may lead to a compromised immune system. A more directed strategy would be to re‐enforce tolerance of the autoaggressive T cells that drive tissue inflammation and injury. In this study, we have investigated whether the course of experimental autoimmune encephalomyelitis (EAE) in mice and marmosets can be altered by a potent tolerizing fusion protein. In addition, a multi‐parameter immunological analysis was performed in marmosets to assess whether the treatment induces modulation of EAE‐associated cellular and humoral immune reactions. The fusion protein, CTA1R9K‐hMOG10–60‐DD, contains a mutated cholera toxin A1 subunit (CTA1R9K), a dimer of the Ig binding D region of Staphylococcus aureus protein A (DD), and the human myelin oligodendrocyte glycoprotein (hMOG) sequence 10–60. We observed that intranasal application of CTA1R9K‐hMOG10–60‐DD seems to skew the immune response against myelin oligodendrocyte glycoprotein (MOG) towards a regulatory function. We show a reduced number of circulating macrophages, reduced MOG‐induced expansion of mononuclear cells in peripheral blood, reduced MOG‐induced production of interleukin (IL)‐17A in spleen, increased MOG‐induced production of IL‐4 and IL‐10 and an increased percentage of cells expressing programmed cell death‐1 (PD‐1) and CC chemokine receptor 4 (CCR4). Nevertheless, the treatment did not detectably change the EAE course and pathology. Thus, despite a detectable effect on relevant immune parameters, the fusion protein failed to influence the clinical and pathological outcome of disease. This result warrants further development and improvement of this specifically targeted tolerance inducing therapy.     

Non‐invasive visual evoked potentials to assess optic nerve involvement in the dark agouti rat model of experimental autoimmune encephalomyelitis induced by myelin oligodendrocyte glycoprotein

Experimental autoimmune encephalomyelitis (EAE) is the primary disease model of multiple sclerosis (MS), one of the most diffused neurological diseases characterized by fatigue, muscle weakness, vision loss, anxiety and depression. EAE can be induced through injection of myelin peptides to susceptible mouse or rat strains. In particular, EAE elicited by the autoimmune reaction against myelin oligodendrocyte glycoprotein (MOG) presents the common features of human MS: inflammation, demyelination and axonal loss. Optic neuritis affects visual pathways in both MS and in several EAE models. Neurophysiological evaluation through visual evoked potential (VEP) recording is useful to check visual pathway dysfunctions and to test the efficacy of innovative treatments against optic neuritis. For this purpose, we investigate the extent of VEP abnormalities in the dark agouti (DA) rat immunized with MOG, which develops a relapsing–remitting disease course. Together with the detection of motor signs, we acquired VEPs during both early and late stages of EAE, taking advantage of a non‐invasive recording procedure that allows long follow‐up studies. The validation of VEP outcomes was determined by comparison with ON histopathology, aimed at revealing inflammation, demyelination and nerve fiber loss. Our results indicate that the first VEP latency delay in MOG‐EAE DA rats appeared before motor deficits and were mainly related to an inflammatory state. Subsequent VEP delays, detected during relapsing EAE phases, were associated with a combination of inflammation, demyelination and axonal loss. Moreover, DA rats with atypical EAE clinical course tested at extremely late time points, manifested abnormal VEPs although motor signs were mild. Overall, our data demonstrated that non‐invasive VEPs are a powerful tool to detect visual involvement at different stages of EAE, prompting their validation as biomarkers to test novel treatments against MS optic neuritis.     

An MHC anchor-substituted analog of myelin oligodendrocyte glycoprotein 35-55 induces IFN-gamma and autoantibodies in the absence of experimental autoimmune encephalomyelitis and optic neuritis

Previous strategies to ameliorate experimental autoimmune encephalitis (EAE) include the treatment of autoreactive T cells with altered peptide ligands, which contain amino acid substitutions at TCR contact residues. We recently showed that a variant of myelin oligodendrocyte glycoprotein (MOG) 35-55 possessing low affinity for MHC (45D) induced anergy in MOG 35-55-specific T cells and reduced their encephalitogenicity upon adoptive transfer. Here we investigate the characteristics of the primary immune response to this MHC anchor-substituted peptide. Overall, we observed that immunization with 45D resulted in the production of IFN-gamma and anti-MOG 35-55 autoantibodies at levels similar to those of MOG 35-55-immunized mice with active EAE. However, no symptoms of clinical or histological EAE or overt histological optic neuritis were observed in 45D-immunized mice. Consistent with this finding, 45D-immunized mice did not exhibit CD4(+) infiltrates into the CNS. Therefore, MOG 35-55-specific precursors stimulated with a weak ligand (45D) mediate some EAE-associated effector functions but are unable to fully initiate the inflammatory process in the central nervous system that leads to clinical manifestation of EAE.     

Augmentation of demyelination in rat acute allergic encephalomyelitis by circulating mouse monoclonal antibodies directed against a myelin/oligodendrocyte glycoprotein.

In this study the authors have developed a model with which can be studied directly the influence of circulating anti-myelin antibody on the clinical and pathologic course of inflammatory T-cell-mediated experimental allergic encephalomyelitis (EAE) in the rat. EAE was induced by passive transfer of either myelin basic protein (MBP)-activated spleen cells derived from sensitized donors or long-term-cultured MBP-specific T-cell lines. At the onset of the disease, monoclonal antibodies against a myelin/oligodendrocyte glycoprotein (MOG) were injected intravenously. This antigen is exposed on the surface of central nervous system myelin and oligodendrocytes. Intravenous injection of the antibody in the course of T-cell-mediated transfer EAE augmented the severity and duration of clinical signs and resulted in the formation of large, confluent demyelinated plaques.     

TCR vaccination in aluminum adjuvant protects against autoimmune encephalomyelitis

Experimental Allergic Encephalomyelitis (EAE) is a neuroinflammatory, autoimmune disorder in which myelin-reactive Th1 T cells with a restricted TCRVbeta repertoire play a pathogenic role. Here, I show that an engineered single-chain TCR containing dominant TCRValpha/Vbeta encephalitogenic elements, when administered in aluminum adjuvant, generates a marked anti-TCR humoral response that correlated with protection against the development of EAE in Vbeta8-expressing B10.PL but not in Vbeta8-deficient SJL mice. sc-TCR/Al vaccination was highly efficient in preventing murine EAE in a TCR-specific manner through a mechanism involving anti-TCR B cells and/or antibodies. Collectively, these data have important implications for designing preventive or therapeutic strategies combining TCR vaccination with the use of aluminum adjuvant in the treatment of multiple sclerosis and other human autoimmune inflammatory diseases.     

口服髓鞘碱性蛋白诱导免疫耐受治疗实验性自身免疫性脑脊髓炎的研究

目的建立实验性自身免疫性脑脊髓炎（ＥＡＥ）动物模型,探讨口服自身抗原诱导免疫耐受对大鼠ＥＡＥ的防治作用。方法在普通Ｗｉｓｔａｒ大鼠经１次足跖真皮内注射完全弗氏佐剂－豚鼠全脊髓匀浆或完全弗氏佐剂－髓鞘碱性蛋白乳剂加百日咳疫苗诱发ＥＡＥ疾病;另在大鼠致炎前及发病后口服髓鞘碱性蛋白（ＭＢＰ）,观察其对ＥＡＥ的防治作用。结果在Ｗｉｓｔａｒ大鼠成功地诱发了ＥＡＥ,发病率将近９０％。大鼠在致炎前口服ＭＢＰ,可明显推迟ＥＡＥ发病时间,降低ＥＡＥ发病率,使神经组织病理改变明显改善。大鼠发生ＥＡＥ后给予ＭＢＰ,可明显控制发病动物的病情,使病程缩短及减轻患鼠神经组织的炎症程度。另外,在耐受鼠由ＭＢＰ引起的迟发型超敏反应（ＤＴＨ）以及体外针对ＭＢＰ的淋巴细胞增殖反应也明显受到抑制。结论口服ＭＢＰ可引起特异性的免疫耐受,从而产生对实验性自身免疫性脑脊髓炎的防治作用     

Linkage analysis of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis in the rat identifies a locus controlling demyelination on chromosome 18.

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the central nervous system (CNS) with a complex etiology comprising a genetically determined predisposition and a suspected auto- immune pathogenesis. Experimental autoimmune encephalomyelitis (EAE) is an animal model for MS, which can be used to define susceptibility loci for autoimmune neuroinflammation. We have recently established a chronic relapsing EAE model characterized by inflammation and focal demyelination in the CNS by immunizing a variety of rat strains with the CNS-specific myelin oligodendrocyte glycoprotein (MOG). This model is more MS-like than any other rodent EAE model described up to now. Here we present the first systematic genome search for chromosomal regions linked to phenotypes of MOG-induced EAE in a (DA x ACI) F(2)intercross. A genome-wide significant susceptibility locus linked to demyelination was identified on chromosome 18. This region has not been described in inflammatory diseases affecting other organs and the responsible gene or genes may thus be nervous system specific. Other chromosomal regions showing suggestive linkage to phenotypes of MOG-induced EAE were identified on chromosomes 10, 12 and 13. The chromosome 10 and 12 regions have previously been linked to arthritis in DA rats, suggesting that they harbour immunoregulatory genes controlling general susceptibility to autoimmune diseases. We conclude that identification of susceptibility genes for MOG-induced EAE on rat chromosomes 10, 12, 13 and 18 may disclose important disease pathways for chronic inflammatory demyelinating diseases of the CNS such as MS.