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Experimental autoimmune encephalomyelitis (EAE) is a CD4+ T cell disease of the central nervous system (CNS) characterized by mononuclear cell infiltration, demyelination, and paralysis. Recent studies describing the relationship of chemokine expression with development of clinical disease have led to the hypothesis that distinct chemokine receptors corresponding to specific ligands are expressed by CNS-infiltrating antigen-specific encephalitogenic T cells as well as host-derived bystander T cells and monocytes. In an effort to study encephalitogenic T cell chemokine receptor expression, we examined CC chemokine receptor expression from resting, activated, and CNS-isolated CD4+ T cells. CCR1, CCR2, CCR3, CCR5, CCR6, CCR7, and CCR8 mRNA is expressed by normal CD4+ T cells. In vitro activated T cells expressed CCR1, CCR2, CCR3, CCR5, CCR6, CCR7, and CCR8 mRNA as well as CCR4. After EAE induction, CCR1 mRNA was expressed by donor-derived encephalitogenic and host-derived CD4+ T cells isolated only from CNS and not from spleen. In vivo neutralization of the CCR1 ligand, macrophage inflammatory protein-1α (CCL3), resulted in less encephalitogenic CD4+ T cell CNS infiltration. These results demonstrate the importance of CC chemokine receptor expression by CD4+ encephalitogenic T cells for CNS infiltration and subsequent disease development. J. Neurosci. Res. 66:705–714, 2001. © 2001 Wiley-Liss, Inc.

Chemokines and their receptors are large families of inflammatory molecules responsible for a number of biologic functions including the accumulation of leukocytes at tissue sites. Over the past 8 years, a number of studies have indicated a role for chemokines in the pathogenesis of CNS inflammatory diseases. This minireview provides a brief summary of our current knowledge of chemokines and CNS inflammatory diseases including experimental autoimmune encephalomyelitis, multiple sclerosis, virus-induced demyelinating diseases, Alzheimer's disease, and central nervous system bacterial-induced diseases.

Experimental autoimmune encephalomyelitis (EAE) is a CD4+ T lymphocyte–mediated disease of the central nervous system (CNS) characterized by mononuclear cell infiltration, demyelination, and paralysis. We previously demonstrated a role for chemokines in acute and relapsing EAE pathogenesis. Presently, we investigated the role of CC chemokine receptor 2 (CCR2) in acute EAE. CCR2−/− mice did not develop clinical EAE or CNS histopathology, and showed a significant reduction in T cell– and CNS-infiltrating CD45highF4/80+ monocyte subpopulations. Peripheral lymphocytes from CCR2−/− mice produced comparable levels of interferon-gamma (IFN-γ) and interleukin (IL)-2 in response to antigen-specific restimulation when compared with control mice. Adoptively transferred myelin oligodendrocyte glycoprotein 35-55–specific T cells lacking expression of CCR2 were able to induce EAE, whereas CCR2−/− recipients of wild-type T cells failed to develop disease. These results suggest that CCR2 expression on host-derived mononuclear cells is critical for disease induction.

Experimental autoimmune encephalomyelitis (EAE) is a T lymphocyte-mediated disease of the central nervous system (CNS), characterized by mononuclear cell infiltration and demyelination resulting in paralysis. We examined CC chemokine expression in the CNS throughout the entire course of the disease and found that the production of macrophage inflammatory protein (MIP)-1alpha correlated with increasing acute disease severity and remained elevated throughout chronic, relapsing disease. In contrast, a substantial level of monocyte chemotactic protein (MCP)-1 expression was not observed until late in acute disease and continued to be evident in the relapsing phase of the disease. MCP-1 expression correlated with increasing severity of clinical relapses. Lower levels of RANTES in the CNS were noted throughout the disease course, but showed little correlation with either acute or relapsing disease. Although RANTES expression was observed during the entire course of disease, anti-RANTES treatment had no effect on clinical disease progression. Anti-MCP-1, but not anti-MIP-1alpha, treatment during relapsing EAE decreased clinical severity of relapsing disease. Furthermore, anti-MCP-1 treatment reduced CNS macrophage accumulation during relapsing EAE. These results suggest that MIP-1alpha controls mononuclear cell accumulation during acute EAE, while MCP-1 controls mononuclear cell infiltration during relapsing EAE.

This unit details the materials and methods required for both active induction and adoptive transfer of experimental autoimmune encephalomyelitis (EAE) in the SJL mouse strain using intact proteins or peptides from the two major myelin proteins: proteolipid protein (PLP) and myelin basic protein (MBP). Detailed materials and methods required for the purification of both PLP and MBP are also described. A protocol for isolating CNS-infiltrating lymphocytes in EAE mice is included. Modifications of the specified protocols may be necessary for efficient induction of active or adoptive EAE in other mouse strains. Curr. Protoc. Immunol. 88:15.1.1-15.1.20. © 2010 by John Wiley & Sons, Inc. Keywords: CFA; complete Freund's adjuvant; CNS; central nervous system; EAE; experimental autoimmune encephalomyelitis; MBP; myelin basic protein; MOG; myelin oligodendrocyte glycoprotein; PLP; proteolipid protein

A variety of experimental approaches are currently being evaluated for controlling CD4+ T helper 1 (Th1)-mediated autoimmune pathology. Here, Stephen Miller and William Karpus compare and contrast the efficacies of various antigen-specific regulatory strategies. Particular emphasis is placed on the mechanisms of peripheral immune tolerance and how this may be used in the treatment and analysis of the pathologic T-cell repertoire in autoimmune and virus-induced demyelinating diseases.

We have previously demonstrated that CD4+ suppressor T cells (Ts) inhibit the secretion of interferon (IFN)-gamma, but not interleukin (IL)-2, by effector cells of experimental autoimmune encephalomyelitis (EAE). Moreover, CD4+ Ts appear to regulate IFN-gamma by secretion of transforming growth factor-beta. We now show that CD4+ Ts produce a lymphokine with IL-4 activity in response to a determinant associated with EAE effector cells. CD4+ Ts do not proliferate or secrete IFN-gamma, IL-2, or IL-4 in response to myelin basic protein, nor do CD4+ Ts proliferate or secrete IL-2 when co-cultured with irradiated EAE effector cells. Rather, CD4+ Ts secrete IL-4 when co-cultured with either irradiated effector spleen cells or irradiated encephalitogenic line cells. CD4+ Ts do not secrete IL-4 in response to OVA-primed spleen cells, suggesting that the suppressor cells recognize a determinant specific to encephalitogenic T cells. Furthermore, CD4+ Ts secrete IL-4 when cultured with synthetic T cell receptor (TcR) V beta 8, but not TcR V beta 14 peptide, in the presence of antigen-presenting cells. This response is major histocompatibility complex class II restricted as demonstrated by inhibition of the response with anti-class II monoclonal antibody. These results suggest that CD4+ Ts recognize a determinant associated with TcR on the surface of EAE effector cells and respond by secreting IL-4, in a manner analogous to the Th2 lymphocyte subtype.

Lewis rats immunized with T cell receptor (TCR) variable region peptide V beta 8 in complete Freund's adjuvant (CFA) were protected against experimental autoimmune encephalomyelitis (EAE) induced with myelin basic protein in CFA, although variable protection was also observed in rats injected with control peptide in CFA, or CFA alone. However, this adjuvant-mediated protection could be avoided by immunizing with TCR peptide in incomplete adjuvant (IFA). Clinical, but not histologic EAE was suppressed in rats given V beta 8 peptide in IFA, whereas control animals injected with V beta 14 peptide in IFA, or IFA alone developed severe clinical EAE. Anti-V beta 8 antibodies were present in the sera of all V beta 8-treated rats. These findings lend support to the hypothesis that autoimmune disease can be suppressed by inducing an immune response against the TCR-idiotope of autoreactive T cells.

Suppressor cells that regulate experimental autoimmune encephalomyelitis (EAE) are present in rats that recover from the disease and can protect against the development of active EAE when transferred to normal recipients. Both CD4+ T suppressor cells, known to regulate EAE effector cell lymphokine production, and myelin basic protein (MBP)-primed B cells are required to transfer protection against EAE to normal recipients. Neither CD4+ T suppressor cells nor MBP-primed B cells alone could transfer protection. Moreover, the co-transfer of normal B cells with CD4+ T suppressor cells did not provide protection against EAE. These results suggest that the regulation of EAE and perhaps the recovery from acute clinical disease requires the interaction of two specific subpopulations of regulatory lymphocytes.

(1999). Chemokine regulation of inflammatory-mediated nervous system diseases. Journal of Neurovirology: Vol. 5, No. 1, pp. 1-2.

BackgroundAn endotoxin insult mimics a severe peripheral infection and recent evidence suggests that a single exposure can cause long-term cognitive deficits. A peripheral injection of LPS results in production of pro-inflammatory cytokines, such as IL-1β and TNF-α, in the brain and periphery and these cytokines mediate many effects of the acute phase response including activation of the HPA axis. The chemokine MCP-1 is highly expressed during endotoxemia and although much is known about the importance of MCP-1 in peripheral inflammatory responses to LPS, information about MCP-1 and CNS responses to peripheral LPS is lacking.MethodsC57Bl/6 mice were administered LPS by intraperitoneal (i.p.) injection, serum and brains were collected at several time points, and the time course of MCP-1 protein up-regulation was measured. To examine the role of MCP-1 in activation of the brain during acute systemic inflammation, we injected MCP-1 knockout (MCP-1-/-) or control C57Bl/6 (MCP-1+/+) mice with LPS i.p. and measured the levels of selected cytokines and chemokines in serum and brain extracts 6 hours later. Activated microglia were examined by CD45 immunohistochemistry, and serum corticosterone and ACTH levels were measured by enzyme immunoassay.ResultsWe report that LPS injection induces a robust increase in MCP-1 protein levels in serum and brain, with peak brain levels reached at 6 hrs after LPS administration. MCP-1-/-mice injected with LPS showed higher levels of serum IL-1β and TNF-α compared to LPS-treated MCP-1+/+mice. In contrast, these MCP-1-/-mice showed significantly lower inductions of brain pro-inflammatory cytokines and chemokines, fewer activated microglia, and a reduction in serum corticosterone levels.ConclusionMCP-1-/-mice have decreased brain inflammation after a peripheral LPS insult, despite an exaggerated peripheral response. These data demonstrate an important role for MCP-1 in regulation of brain inflammation after peripheral endotoxemia.

Activation of microglia and astrocytes in experimental autoimmune encephalitis (EAE) has been associated with chemokine induction in the CNS resulting in attraction of inflammatory infiltrate. The role of IL-17 in autoimmune disease has called into question the role of IFN-γ in EAE. In this report we investigate the necessity of IFN-γ receptor signaling in disease induction. To test this we made IFN-γR−/− radiation bone chimeras with animals expressing IFN-γR in the CNS, animals deficient for IFN-γR in the CNS but able to signal in the periphery and a wild-type control (WT). We found IFN-γR expression on astrocytes and microglia was critical for clinical disease symptoms in the adoptive transfer model of EAE. Without IFN-γ activation in the CNS there were no infiltrating leukocytes while in WT and in animals capable of signaling in the CNS there were CD4, CD8, and CD11b infiltrating cells. CCL2, CCL5 and CXCL10 were significantly decreased in CNS homogenates of animals devoid of IFN-γR on astrocytes and microglia compared to WT and mice expressing IFN-γR on peripheral leukocytes. These results argue that IFN-γ activation in the CNS is essential for clinical EAE disease induction. Supported by NIH R01 NS034510.

This article focuses on the distinct role of chemokines and chemokine receptors during CNS inflammation in experimental autoimmune encephalomyelitis (EAE) as an animal model for multiple sclerosis (MS). We review the evidence that chemokines and chemokine receptors have an intrinsic role in regulating and amplifying the inflammatory reactions in EAE or MS leading to disease outcome. A variety of studies examining temporal chemokine expression patterns, using chemokine and chemokine receptor knockout mice as well as administering passive anti-chemokine antibodies indicates that these molecules are critical regulatory components for leukocyte recruitment and/or leukocyte retention in the CNS. Therefore, chemokine and chemokine receptor expression is tightly interrelated to composition of inflammatory cells in CNS lesions and the onset of clinical diseases and provide viable targets for therapeutic intervention.

We characterized the effector cells which mediate experimental autoimmune encephalomyelitis (EAE) on the basis of selective adherence properties. Nylon-nonadherent spleen cells (SpC) from Lewis rats challenged earlier with myelin basic protein (BP) in adjuvant were separated by ‘panning’ on Petri dishes coated with monoclonal antibody (MAb) OX22. OX22 recognizes high molecular weight forms of the leukocyte-common antigen which is present on several cell types, including the CD4-positive T cells which mediate delayed hypersensitivity reactions. We found that the EAE effector cells were enriched in the OX22-adherent T cell population, which supports the hypothesis that delayed hypersensitivity is important in the pathogenesis of this autoimmune disease.

Central nervous system (CNS) depletion of norepinephrine (NE) using 6-hydroxydopamine (6-OHDA) prior to disease induction suppressed the clinical signs of experimental autoimmune encephalomyelitis (EAE). This treatment did not have an effect on the degree of mononuclear cell infiltration when spinal cord sections were examined and stained with hematoxylin and eosin, nor on serum levels of anti-myelin basic protein antibodies. However, investigation of the subpopulations of lymphoid cells within the perivascular lesions showed an increase in cells bearing the T suppressor cell phenotype, OX8+, in the 6-OHDA-treated EAE rats when compared to saline-control-treated EAE rats. Examination of other cellular subsets showed no differences in the numbers of T helper cells, macrophages, or B cells within the lesions of the two groups. Furthermore, histofluorescent estimation of catecholamines in spinal cord sections from 6-OHDA- and saline-control-treated EAE rats demonstrated that catecholamines were indeed depleted in the rats with suppressed clinical EAE. These findings suggest that 6-OHDA depletion of CNS NE may remove an effector amplification mechanism, or trigger a T suppressor cell mechanism, or both, leading to suppression of the effector phase of EAE, clinical paralysis.