Search

Multiple sclerosis (MS) is an autoimmune disorder of the CNS. Different subtypes of the disease have been noted, and characterized by distinct clinical courses and histopathologic manifestations. The most intensively studied animal model of MS, experimental autoimmune encephalomyelitis (EAE), classically leads to deficits in motor functions, and is mediated by T helper cells. Recently, T(H)17 cells were ascribed an even greater pathogenic impact than T(H)1 cells, but new findings render this view controversial. Although classic EAE has been an invaluable tool, it does not cover the entire pathogenic entity of MS. Especially B-cell contribution and autoantibody-dependence are not mirrored adequately: therefore, new B-cell-dependent models, such as MP4-induced EAE, have been introduced. Furthermore, certain symptoms and the spontaneous onset of MS are not featured in classic EAE. Herein, atypical and spontaneous EAE models can be used for investigation of common symptoms, such as tremor and ataxia, as well as spontaneous disease development. MS displays a marked inter-individual heterogeneity, and no single model will be able to cover all features. Thus, depending on the objective of one's study, the appropriate EAE model has to be carefully chosen. In addition, refined models should be designed to gain a more complete understanding of MS.

In multiple sclerosis (MS) lymphoid follicle-like aggregates have been reported in the meninges of patients. Here we investigated the functional relevance of B cell infiltration into the central nervous system (CNS) in MP4-induced experimental autoimmune encephalomyelitis (EAE), a B cell-dependent mouse model of MS. In chronic EAE, B cell aggregates were characterized by the presence of CXCL13(+) and germinal center CD10(+) B cells. Germline transcripts were expressed in the CNS and particularly related to TH17-associated isotypes. We also observed B cells with restricted VH gene usage that differed from clones found in the spleen. Finally, we detected CNS-restricted spreading of the antigen-specific B cell response towards a myelin and a neuronal autoantigen. These data imply the development of autonomous B cell-mediated autoimmunity in the CNS in EAE - a concept that might also apply to MS itself.

Multiple sclerosis (MS) is an autoimmune disorder of the CNS. Different subtypes of the disease have been noted, and characterized by distinct clinical courses and histopathologic manifestations. The most intensively studied animal model of MS, experimental autoimmune encephalomyelitis (EAE), classically leads to deficits in motor functions, and is mediated by T helper cells. Recently, T(H)17 cells were ascribed an even greater pathogenic impact than T(H)1 cells, but new findings render this view controversial. Although classic EAE has been an invaluable tool, it does not cover the entire pathogenic entity of MS. Especially B-cell contribution and autoantibody-dependence are not mirrored adequately: therefore, new B-cell-dependent models, such as MP4-induced EAE, have been introduced. Furthermore, certain symptoms and the spontaneous onset of MS are not featured in classic EAE. Herein, atypical and spontaneous EAE models can be used for investigation of common symptoms, such as tremor and ataxia, as well as spontaneous disease development. MS displays a marked inter-individual heterogeneity, and no single model will be able to cover all features. Thus, depending on the objective of one's study, the appropriate EAE model has to be carefully chosen. In addition, refined models should be designed to gain a more complete understanding of MS.

Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system. The remitting-relapsing experimental autoimmune encephalomyelitis (EAE) in the SJL mouse strain is a common animal model for MS and similar to the human disease it is considered to be T helper cell mediated. Besides interferon-γ secreting TH1 cells in particular the TH17 subset is believed to be highly pathogenic. Spreading of the TH1 and TH17 response to newly emerging determinants has been used to explain clinical disease relapse, but if the magnitude of the TH1/TH17 response is linked to clinical relapse severity has remained unresolved. Here, we assessed clinical EAE severity, the extent of spinal cord histopathology and the magnitude of the antigen-specific T helper cell and autoantibody response in proteolipid protein peptide 139–151 (PLP:139–151)-immunized SJL mice in clinical remission and relapse. We demonstrate that spinal cord histopathology comprised inflammation, demyelination as well as axonal loss and correlated well with clinical disease severity. Although the degree of spinal cord histopathology and clinical severity was separated from the PLP:139–151-specific TH1/TH17 cell and antibody response, it was linked to the number of infiltrating macrophages and activated microglia. In particular, there was a correlation between their secretion product interleukin-1β and the degree of axonal loss. Although CD4+ T cells seem to be mainly involved in disease initiation, we suggest that it is the downstream activation of the innate immune response that defines the magnitude of the disease outcome. © 2012 Wiley Periodicals, Inc.

Multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) have long been regarded as primarily T helper cell type 1-mediated diseases. However, recent evidence suggests that T(H)17 cells, a mostly unexplored subset of T helper cells, may be even more pathogenic than T(H)1 cells. In the EAE model, this cell type is crucial for the recruitment of leukocytes into the CNS and for triggering parenchymal inflammation. In humans, T(H)17 cells are found in acutely active and on the borders of chronically active lesions. Overall, CD4(+) T cells only recognize antigens presented on MHC class II complexes, and these are seldom found in the CNS. MHC class I, in contrast, can be induced on neurons and myelin. This also makes CD8(+) T cells promising candidates as effector cell types. Indeed, CD8(+) T cells outnumber CD4(+) T cells in the lesions of MS patients, and can induce axonal pathology. New data on B cells have likewise stimulated unconventional paths of reasoning about the disease. B cells can contribute to the pathogenesis by secreting autoantibodies and presenting antigens to T cells. By the formation of ectopic B cell aggregates in the CNS, B cell differentiation and response can take place remote from the periphery, thus autonomously fueling pathology. In addition, cells of the innate immune system including macrophages, dendritic cells and mast cells are present in the inflamed CNS. On the one hand, these cells can recognize pathogen-associated molecular patterns via Toll-like receptors (TLRs), generating proinflammatory signals that trigger adaptive immune responses. On the other hand, these cells support the autoimmune process by the secretion of effector molecules such as nitric oxide (NO). Apart from a solely pathogenic autoimmune role, regulatory T cells, NK cells and NKT cells can suppress autoreactive cells. In this paper, we review data on how a complex network of immune mechanisms is involved in the pathogenesis of MS and EAE. We also critically reevaluate the traditional CD4/T(H)1 paradigm.