Symptoms Of Experimental Autoimmune Encephalomyelitis Research Articles

Apolipoprotein E-Derived Peptides Ameliorate Clinical Disability and Inflammatory Infiltrates into the Spinal Cord in a Murine Model of Multiple Sclerosis

Apolipoprotein E (apoE), well known to play a role in lipid transport and cholesterol metabolism, also exerts anti-inflammatory and neuroprotective effects in the central nervous system. Recent clinical and genetic studies display an association between apoE genotype (APOE) and the progression and severity of multiple sclerosis, raising the possibility that modulation of apoE may be a novel treatment for multiple sclerosis. Using a murine experimental autoimmune encephalomyelitis (EAE) model of human multiple sclerosis, we found that a peptidomimetic of apoE protein, COG133, substantially reduces the clinical symptoms of EAE and promotes remission from the disability when administered before or after onset of disease. Most notably, fusion of COG133 to a protein transduction domain creates COG112, a modified apoE-mimetic peptide with significantly enhanced anti-inflammatory bioactivities in vitro, and improved therapeutic effects on EAE in vivo, which renders a nearly full remission from the disability. Histopathological analysis showed that COG112 and COG133 attenuated demyelination and significantly diminished the number of peripheral cells infiltrating into the spinal cord. ApoE mimetics also interfered with several mechanisms relevant to the pathogenesis of EAE and multiple sclerosis, including activation of macrophages, subsequent production of nitric oxide and inflammatory cytokines, and lymphocyte proliferation. These data suggest that apoE mimetics represent a multidimensional therapeutic for multiple sclerosis capable of inhibiting the inflammatory cascade, modulating immune cell function, and reducing clinical signs, which may have novel utility for the treatment of inflammatory autoimmune diseases.

A sulfated disaccharide derived from chondroitin sulfate proteoglycan protects against inflammation‐associated neurodegeneration

Chondroitin sulfate proteoglycan (CSPG), a matrix protein that occurs naturally in the central nervous system (CNS), is considered to be a major inhibitor of axonal regeneration and is known to participate in activation of the inflammatory response. The degradation of CSPG by a specific enzyme, chondroitinase ABC, promotes repair. We postulated that a disaccharidic degradation product of this glycoprotein (CSPG-DS), generated following such degradation, participates in the modulation of the inflammatory responses and can, therefore, promote recovery in immune-induced neuropathologies of the CNS, such as experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune uveitis (EAU). In these pathologies, the dramatic increase in T cells infiltrating the CNS is far in excess of the numbers needed for regular maintenance. Here, we show that CSPG-DS markedly alleviated the clinical symptoms of EAE and protected against the neuronal loss in EAU. The last effect was associated with a reduction in the numbers of infiltrating T cells and marked microglia activation. This is further supported by our in vitro results indicating that CSPG-DS attenuated T cell motility and decreased secretion of the cytokines interferon-gamma and tumor necrosis factor-alpha. Mechanistically, these effects are associated with an increase in SOCS-3 levels and a decrease in NF-kappaB. Our results point to a potential therapeutic modality, in which a compound derived from an endogenous CNS-resident molecule, known for its destructive role in CNS recovery, might be helpful in overcoming inflammation-induced neurodegenerative conditions.

Secreted phospholipase A2 activity in experimental autoimmune encephalomyelitis and multiple sclerosis

BackgroundThere is increased interest in the contribution of the innate immune system to multiple sclerosis (MS), including the activity of acute inflammatory mediators. The purpose of this study was to test the involvement of systemic secreted phospholipase A2 (sPLA2) enzymes in experimental autoimmune encephalomyelitis (EAE), an MS model, and to determine if enzyme activity is elevated in MS patients.MethodsA non-invasive urinary assay was developed in order to monitor enzymatically active sPLA2 levels in Dark Agouti rats after induction of EAE. Some Rats were treated with nonapeptide CHEC-9, an uncompetitive sPLA2 enzyme inhibitor, during the initial rise in urinary enzyme levels. Body weight and clinical EAE score were measured for 18 days post immunization (PI), after which the rats were sacrificed for H&E and myelin staining, and for ED-1 immunocytochemistry, the latter to quantify macrophages and activated microglia. The urinary sPLA2 assay was also applied to un-timed samples collected from a cross section of 44 MS patients and 14 healthy controls.ResultsMean levels of enzymatically active sPLA2 in the urine increased following immunization and peaked between days 8–10 PI which was just prior to the onset of EAE symptoms. At this time, a transient attenuation of activity was detected in the urine of CHEC-9 treated rats consistent with the activity-dependent properties of the inhibitor. The peptide also reduced or abolished EAE symptoms compared to vehicle-injected controls. Histopathological changes in the spinal cords of the EAE rats correlated generally with clinical score including a significant reduction in ED-1+ cells after peptide treatment. Multiple Sclerosis patients also showed elevations in sPLA2 enzyme activity. Mean levels of sPLA2 were increased 6-fold in the urine of patients with active disease and 4-fold for patients in remission, regardless of immunomodulating therapy.ConclusionThe results suggest that sPLA2 enzymes, traditionally thought to be part the acute phase inflammatory response, are therapeutic targets for MS.

Intravenous immunoglobulin ameliorates experimental autoimmune encephalomyelitis and reduces neuropathological abnormalities when administered prophylactically

Background and methods: Immunomodulation with intravenous immunoglobulin (IVIG) represents a way of interfering with the disease process in multiple sclerosis (MS). In this study, the effects of IVIG on neurological symptoms and central nervous system (CNS) pathology were evaluated in experimental autoimmune encephalomyelitis (EAE), an MS animal model. EAE was induced in susceptible Dark Agouti rats by active immunization with a spinal cord homogenate, and infusions of 1 g/kg IVIG were given prophylactically or therapeutically.Results: The administration of IVIG at the time of immunization significantly suppressed the development of neurological symptoms compared with infusions of placebo (mean EAE score 0.6±0.3 versus 2.3±0.4). Moreover, the prophylactic IVIG administration resulted in a significant inhibition of the inflammatory response in CNS tissue (inflammation score 1.1±0.2 versus 1.8±0.2 after placebo). No beneficial effects were obtained by therapeutic IVIG infusions as the EAE disease course and the degree of inflammation and demyelination in the CNS were not different from animals receiving treatment with placebo.Conclusions: The present study indicates that IVIG reduces the symptoms of EAE by suppression of the CNS inflammation that characterizes CNS pathology in these animals. Taking into account data from clinical trials of IVIG in MS, the results further suggest that IVIG acts primarily during the induction phase of the immune response thus preventing the development of relapses in MS.

Blocking ion channel KCNN4 alleviates the symptoms of experimental autoimmune encephalomyelitis in mice

The KCNN4 potassium-ion channel has been reported to play an important role in regulating antigen-induced T cell effector functions in vitro. This study presents the first evidence that a selective KCNN4 blocker, TRAM-34, confers protection against experimental autoimmune encephalomyelitis (EAE) in the mouse model. Treatment with the KCNN4 blocker did not prevent infiltration of T cells in the spinal cord, but resulted in the reduction of both the protein and the message levels of TNF-alpha and IFN-gamma as well as the message levels of several other pro-inflammatory molecules in the spinal cord. Plasma concentrations of TRAM-34 within a 24-h period were between the in vitro IC(50) and IC(90) values for the KCNN4 channel. The effect of TRAM-34 was reversible, as indicated by the development of clinical EAE symptoms within 48 h after withdrawal of treatment. In summary, our data support the idea that KCNN4 channels play a critical role in the immune response during the development of MOG-induced EAE in C57BL/6 mice.

Severe T-cell depletion from the PALS leads to altered spleen composition in common marmosets with experimental autoimmune encephalomyelitis (EAE)

Recent data suggest that the spleen is a crucial component of the immune system in the development of experimental autoimmune encephalomyelitis (EAE) in marmoset monkeys. Using immunohistochemistry, we investigated changes in the distribution of leukocytes in the spleen associated with clinical symptoms of EAE. Animals without EAE displayed well-developed T- and B-cell areas, germinal centers and red pulp. In contrast, a marked depletion of periarteriolar T cells with preservation of other elements was found in animals with clinical EAE. These findings suggest that immune responses within the spleen are impaired during a paralysing inflammatory process in the central nervous system.

Phenidone, a dual inhibitor of cyclooxygenases and lipoxygenases, ameliorates rat paralysis in experimental autoimmune encephalomyelitis by suppressing its target enzymes

This study examined whether phenidone, a dual inhibitor of cyclooxygenase (COX) and lipoxygenase (LOX), affects the clinical symptoms of experimental autoimmune encephalomyelitis (EAE) in the rat, and the expression of both COX-1/-2 and 5-LOX in EAE spinal cords. Oral phenidone (200 mg/kg) significantly suppressed the incidence and clinical severity of EAE paralysis. Western blot analysis showed that phenidone significantly inhibited the increases in COX-1/-2 and 5-LOX in the spinal cords of rats with EAE. This finding was paralleled by immunohistochemical observations. Overall, these findings suggest that COX-1/-2 and 5-LOX are important inflammatory mediators in the pathogenesis of EAE, and that the inhibition of both COX and LOX ameliorates the autoimmune disorder of the central nervous system.

Novel Immunosuppressive Therapy by M2000 in Experimental Multiple Sclerosis

The therapeutic potency of M2000 (β-D-mannuronic acid), a novel designed nonsteroidal anti-inflammatory drug with immunosuppressive property in T-cell-mediated autoimmune disease, was tested. The influence of M2000 on myelin basic protein (MBP)-induced experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, was assessed. M2000 at two doses, 40 and 80 mg/kg/day, was administered intraperitoneally (i.p.) to prevention and treatment groups, respectively. Onset of i.p. injections of M2000 to prophylactic and therapeutic groups was day-1 and day-7 postimmunization. The WEHI-164 cell line was used for assaying the tolerability against M2000. The results of this experiment showed that the treatment of EAE with M2000 could significantly suppress disease development both prophylactically and therapeutically; the onset and symptoms of EAE in Lewis rats could be suppressed following the administration of M2000. Clinical improvement was accompanied by a marked decrease in mean numbers of vessels with perivascular cellular infiltration in M2000-treated rats compared with nontreated control. Disease suppression was associated with a marked suppression of MBP-specific T-cell reactivity in vitro, without any evidence for a generalized impairment of T-cell activity. Moreover, M2000 also showed a very high tolerability compared with certain steroidal and nonsteroidal anti-inflammatory drugs. Collectively, our data suggest that M2000 may provide a novel therapeutic option for T-cell-mediated autoimmune diseases in animal models and possibly in humans.

Nogo signaling and non‐physical injury‐induced nervous system pathology

The Nogo gene products were described first as myelin-associated inhibitors that prevent neuronal regeneration upon injury. Recent findings have also implicated Nogo in several neuronal pathologies that are not induced by physical injury. Nogo-A may be an important determinant of autoimmune demyelinating diseases, as active immunization with Nogo-A fragments attenuates the symptoms of experimental autoimmune encephalomyelitis (EAE). Nogo-A levels are elevated markedly in hippocampal neurons of patients with temporal lobe epilepsy (TLE), in brain and muscle of patients with amyotrophic lateral sclerosis (ALS), and in schizophrenic patients. Concrete evidence for a direct role of Nogo-A in the latter neuropathies is not yet available, but such a role is logically in line with new findings associated with localization of Nogo-A and Nogo-Nogo-66 receptor (NgR)-mediated signaling. We speculate on possible linkages between the effect of aberrant elevation of Nogo levels and the signaling consequences that could lead to nervous system pathology.

Spread and Replication of and Immune Response to γ 1 34.5-Negative Herpes Simplex Virus Type 1 Vectors in BALB/c Mice

We have previously shown that intracranial infection of herpes simplex virus type 1 (HSV-1) vector R8306 expressing interleukin-4 (IL-4) can abolish symptoms of experimental autoimmune encephalomyelitis, which is used as a model for human multiple sclerosis (Broberg et al., Gene Ther. 8:769-777, 2001). The aim of the current study was to search for means other than intracranial injection to deliver HSV-derived vectors to the central nervous system of mice. We also aimed to study the replication efficiency of these vectors in nervous system tissues and to elucidate the effects of the viruses on the immune response. We studied the spread and replication of the following viruses with deletions in neurovirulence gene gamma(1)34.5: R3616, R849 (lacZ transgene), R3659 (alpha-tk), R8306 (murine IL-4 transgene), and R8308 (murine IL-10 transgene). The samples were taken from trigeminal ganglia and brains of BALB/c mice after corneal, intralabial, and intranasal infection, and the viral load was examined by viral culture, HSV DNA PCR, and VP16 reverse transcription (RT)-PCR. The results show that (i) intranasal infection was the most efficient means of spread to the central nervous system (CNS) besides intracranial injection; (ii) the viruses did not grow in the culture from the brain samples, but the viral DNA persisted even until day 21 postinfection; (iii) viral replication, as observed by VP16 mRNA RT-PCR, occurred mainly on days 4 and 7 postinfection in trigeminal ganglia and to a low extent in brain; (iv) R3659, R8306, and R8308 showed reactivation from the trigeminal ganglia in explant cultures; (v) in the brain, the vectors spread to the midbrain more efficiently than to other brain areas; and (vi) the deletions in the R3659 genome significantly limited the ability of this virus to replicate in the nervous system. The immunological studies show that (i) the only recombinant to induce IL-4 mRNA expression in the brain was R8306, the gamma interferon response was very low in the brain for R3659 and R8306, and the IL-23p19 response to R8306 decreased by day 21 postinfection, unlike for the other viruses; (ii) Deltagamma(1)34.5 HSV vectors modulated the subsets of the splenocytes differently depending on the transgene; (iii) R3659 infection of the nervous system induces expression and production of cytokines from the stimulated splenocytes; and (iv) HSV vectors expressing IL-4 or IL-10 induce expression and production of both of the Th2-type cytokines from splenocytes. We conclude that the intranasal route of infection is a possible means of delivery of Deltagamma(1)34.5 HSV vectors to the CNS in addition to intracranial infection, although replication in the CNS remains minimal. The DNA of the HSV vectors is able to reside in the brain for at least 3 weeks. The features of the immune response to the vectors must be considered and may be exploited in gene therapy experiments with these vectors.

Andrographolide Interferes with T Cell Activation and Reduces Experimental Autoimmune Encephalomyelitis in the Mouse

Andrographolide is a bicyclic diterpenoid lactone derived from extracts of Andrographis paniculata, a plant indigenous to South Asian countries that shows anti-inflammatory properties. The molecular and cellular bases for this immunomodulatory capacity remain unknown. Here, we show that andrographolide is able to down-modulate both humoral and cellular adaptive immune responses. In vitro, this molecule was able to interfere with T cell proliferation and cytokine release in response to allogenic stimulation. These results were consistent with the observation that T cell activation by dendritic cells (DCs) was completely abolished by exposing DCs to andrographolide during antigen pulse. This molecule was able to interfere with maturation of DCs and with their ability to present antigens to T cells. Furthermore, in vivo immune responses such as antibody response to a thymus-dependent antigen and delayed-type hypersensitivity were drastically diminished in mice by andrographolide treatment. Finally, the ability of andrographolide to inhibit T cell activation was applied to interfere with the onset of experimental autoimmune encephalomyelitis (EAE), an inflammatory demyelinating disease of the central nervous system that is primarily mediated by CD4(+) T cells and serves as an animal model for human multiple sclerosis. Treatment with andrographolide was able to significantly reduce EAE symptoms in mice by inhibiting T cell and antibody responses directed to myelin antigens. Our data suggest that andrographolide is able to efficiently block T cell activation in vitro, as well as in vivo, a feature that could be useful for interfering with detrimental T cell responses.

CNI-1493 mediated suppression of dendritic cell activation in vitro and in vivo

The tetravalent guanylhydrazone CNI-1493 (CNI-1493) has been shown to inhibit macrophage activation, reduce systemic inflammation as well as proinflammatory cytokine production. Here we report for the first time that CNI-1493 also influences the biology of dendritic cells (DC). In order to become potent T cell stimulators of DC have to mature. Interestingly, when CNI-1493 was added to the maturation stimulus the expression of a typical DC-maturation marker i.e. CD83 was reduced. Subsequent functional in vitro analyses showed that DC-mediated T-cell stimulation was clearly reduced in CNI-1493-treated DC, underlining the functional impact that CNI-1493 on DC biology. Furthermore, the effect of CNI-1493 was analyzed in vivo using the experimental autoimmune encephalomyelitis (EAE) model in C57BL/6 mice. Interestingly, in a prophylactic treatment regimen CNI-1493 prevented the paralysis associated with EAE almost completely. In addition, when applied in an early therapeutic setting CNI-1493 also reduced the clinical EAE symptoms. In summary, we show for the first time, that in addition to the earlier reported effects on macrophages, CNI-1493 also influences the function and biology of DC. Since DC are the only antigen-presenting cells (APC) known today to be able to prime naı̈ve T cells, the findings reported herein are highly relevant for the therapeutic application of CNI-1493.

Effect of pioglitazone treatment in a patient with secondary multiple sclerosis

BackgroundLigands of the peroxisome proliferator-activated receptor-gamma (PPARγ) induce apoptosis in activated T-lymphocytes and exert anti-inflammatory effects in glial cells. Preclinical studies have shown that the thiazolidinedione pioglitazone, an FDA-approved PPARγ agonist used to treat type 2 diabetes, delays the onset and reduces the severity of clinical symptoms in experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS). We therefore tested the safety and therapeutic potential of oral pioglitazone in a patient with secondary MS.Case presentationThe rationale and risks of taking pioglitazone were carefully explained to the patient, consent was obtained, and treatment was initiated at 15 mg per day p.o. and then increased by 15 mg biweekly to 45 mg per day p.o. for the duration of the treatment. Safety was assessed by measurements of metabolic profiles, blood pressure, and edema; effects on clinical symptoms were assessed by measurement of cognition, motor function and strength, and MRI. Within 4 weeks the patient exhibited increased appetite, cognition and attention span. After 12 months treatment, body weight increased from 27.3 to 35.9 kg (32%) and maintained throughout the duration of the study. Upper extremity strength and coordination improved, and increased fine coordination was noted unilaterally after 8 months and bilaterally after 15 months. After 8 months therapy, the patient demonstrated improvement in orientation, short-term memory, and attention span. MRIs carried out after 10 and 18 months of treatment showed no perceptible change in overall brain atrophy, extent of demyelination, or in Gd-enhancement. After 3.0 years on pioglitazone, the patient continues to be clinically stable, with no adverse events.ConclusionsIn a patient with secondary progressive MS, daily treatment with 45 mg p.o. pioglitazone for 3 years induced apparent clinical improvement without adverse events. Pioglitazone should therefore be considered for further testing of therapeutic potential in MS patients.

Hypotension with intravenous immunoglobulin therapy: importance of pH and dimer formation

Therapy with intravenous immunoglobulin preparations has been used effectively in a wide range of conditions. Although generally well tolerated, intravenous immunoglobulin preparations may be associated with transient hypotension in some patients. This study examined the role of different immunoglobulin G fractions in the development of intravenous immunoglobulin-induced hypotension in an anaesthetized rat model and assessed the effects of a new liquid immunoglobulin prepared at a low pH on both the formation of immunoglobulin G dimers and the development of hypotension. The effects of this new preparation in an experimental autoimmune encephalomyelitis model were also evaluated. Results from the haemodynamic studies indicated that immunoglobulin G dimers in polyclonal immunoglobulin G are responsible for the hypotensive events associated with some immunoglobulin preparations. They also showed that adjustment to an acidic pH results in the rapid dissociation of immunoglobulin G dimers and prevents the development of hypotension. Additional experiments demonstrated that only immunoglobulin G dimers with a functional Fc fragment can bind to Fc γ receptors on macrophages to induce the release of blood pressure-lowering mediators. Moreover, essentially monomeric Fc fragments can block the blood pressure-lowering effects of immunoglobulin G dimers. Preparation of a new liquid intravenous immunoglobulin with the pH adjusted to 4.3 prevents the formation of immunoglobulin G dimers even over long-term storage and does not significantly affect blood pressure in a rat model. This preparation is as effective as other intravenous immunoglobulin preparations in ameliorating symptoms of experimental autoimmune encephalomyelitis. These results, like those from previous studies, indicate that preparation of intravenous immunoglobulin at a low pH substantially reduces immunoglobulin G dimerization; this effect significantly decreases the potential for intravenous immunoglobulin to induce hypotension without reducing its clinically relevant biological activity.

Iron-Deficient Mice Fail to Develop Autoimmune Encephalomyelitis

Determinations of the effects of iron status on the immune system are complicated by the fact that microorganisms and immune cells both utilize iron. To determine the role of iron in immune function, we utilized a model [experimental autoimmune encephalomyelitis (EAE)] in which a strong antigen-specific CD4+ T-cell response develops in the absence of infection. EAE is an autoimmune disease frequently used as a model for the human disease multiple sclerosis (MS). EAE was induced in B10.PL mice fed low iron (1 mg/kg), normal iron (10 mg/kg) or high iron (160 mg/kg) diets that were replete in all other nutrients. Liver iron measurements verified iron status, i.e., low iron mice had 1.9 micro mol/g tissue, normal iron mice, 3.27 micro mol/g tissue and high iron mice, 5.35 micro mol/g tissue. EAE symptoms were most severe in normal iron mice, and EAE did not develop in low iron mice. The incidence of EAE was 71% in normal iron mice, 62% in iron-overloaded mice and 0% in iron-deficient mice. Two of seven mice in the normal iron group developed severe EAE and were euthanized. None of the iron-overloaded mice developed severe EAE. Other measures of EAE severity were similar in the normal and iron-overloaded mice. The data suggest that iron deficiency provides protection from the development of EAE and that iron excess with its potential contribution to free radical formation was not an important factor. The mechanism of EAE inhibition in iron-deficient mice likely involves the delivery and metabolism of iron for optimal CD4+ T-cell development.

Exacerbation of experimental autoimmune encephalomyelitis in rodents infected with murine gammaherpesvirus-68.

Viral infections have long been suspected to play a role in the pathogenesis of multiple sclerosis. In the present study, two different rodent models of experimental autoimmune encephalomyelitis (EAE) were used to demonstrate the ability of murine gammaherpesvirus‐68 (γHV‐68) to exacerbate development of neurological symptoms. SJL mice received UV‐inactivated γHV‐68 or intranasalγHV‐68, followed by immunization against proteolipid‐protein peptide 139–151. Infected mice became moribund within 10 days post‐immunization, whereas mice exposed to UV‐inactivated γHV‐68 recovered. In the second model, Lewis rats were exposed to UV‐inactivated γHV‐68 or to γHV‐68, followed by passive transfer of encephalitogenic T lymphocytes specific for myelin basic protein. Consistently, infected rats had higher clinical scores, and this result was observed during acute or latent γHV‐68 infection. It is unlikely that this γHV‐68‐induced exacerbation was due to significant viral replication within the central nervous system since nested PCR, viral plaque assays, and infectious‐centers assays demonstrated no detectable virus in spinal cords or brains of infected rodents undergoing EAE. Taken together, these studies demonstrate increased clinical symptoms of EAE in rodents infected by a gammaherpesvirus that has a limited ability to invade the central nervous system.

Optimization of an animal model of experimental autoimmune encephalomyelitis achieved with a multiple MOG 35–55peptide in C57BL6/J strain of mice

The severity of the experimental autoimmune encephalomyelitis (EAE) induced by peptide myelin oligodendrocyte glycoprotein 35–55(pMOG 35–55) is thought to be predominantly influenced by the major histocompatibility complex (MHC), so that C57BL6/J mice, on H2 b strain, were only mildly sick. However, it remains unclear as to how non-MHC gene regions affect EAE. To determine whether the immunization protocol could have an influence on clinical signs, C57BL6/J mice were immunized with a multiple antigen peptide (MAP) containing eight pMOG 35–55branches synthesized directly onto a lysine core, myelin oligodendrocyte glycoprotein 35–55–multiple antigen peptide (MOG 35–55–MAP), in complete Freund's adjuvant (CFA). In most of the mice, clinical onset (marked weakness) occurred approximately at day 15. All mice injected with MOG 35–55–MAP had more severe symptoms than those injected with pMOG 35–55, which developed no leg paralysis. All MOG 35–55–MAP-immunized mice developed EAE symptoms, but 50% had primary-progressive EAE, while the other 50% had relapsing–remitting disease. Leukocyte infiltrations, associated with increased glial fibrillary acidic protein (GFAP) expression by reactive astrocytes, were observed around the lateral ventricles and blood vessels in the brain. Significant positive correlations were established between anti-MOG 35–55antibody levels and clinical scores or GFAP positivity in the spinal cord. The heterogeneity of EAE progression, observed in these genetically identical individuals, suggests that the environment rather than the genetics plays a role. This observation is highly pertinent as it corresponds to what is seen in clinical MS.

Maternal deprivation of rat pups increases clinical symptoms of experimental autoimmune encephalomyelitis at adult age

Maternal deprivation of neonatal animals has been shown to induce long-lasting changes in the reactivity of the neuroendocrine system. The aim of the present study was to investigate whether maternal deprivation also affects susceptibility to immune-mediated diseases such as experimental autoimmune encephalomyelitis (EAE) in adult life. To this end, 9-day-old rat pups were subjected to a short-lasting maternal deprivation for a period of 24 h. At the age of 8 weeks, we induced EAE in these rats by immunization with myelin basic protein (MBP) in complete Freund's adjuvant. Our data demonstrate that short-lasting maternal deprivation induces a marked increase in the severity of EAE in the animals in later life. The histopathological evaluation of spinal cord and cerebellum corresponded with the observed differences in clinical symptoms of EAE. Moreover, neonatal maternal deprivation affects macrophage functioning at adult age. In contrast, no differences were observed in in vitro mitogen- and MBP-induced cytokine production by splenocytes. LPS-induced corticosterone release did not differ either between maternally deprived and control animals. We conclude that short-lasting neonatal maternal deprivation of rat pups has long-lasting consequences for macrophage activity and for susceptibility to the inflammatory autoimmune disease EAE.

Protection of marmoset monkeys against EAE by treatment with a murine antibody blocking CD40 (mu5D12).

CD40-CD40 ligand interactions are crucial to cognate interactions between T cells, B cells and antigen-presenting cells (APC), and contribute to non-antigen-specific effector functions of APC in inflammatory disorders. Here we demonstrate that functional blockade of CD40 with an antagonist mouse anti-human CD40 monoclonal antibody (mAb mu5D12) effectively prevents clinical expression of chronic demyelinating experimental autoimmune encephalomyelitis (EAE) in outbred marmoset monkeys, a preclinical model of multiple sclerosis. Anti-CD40 mAb interfered with development of clinical symptoms of marmoset EAE during the treatment period, even when treatment was started several weeks after T cell priming. Magnetic resonance imaging demonstrated inflammatory activity in the brain at initiation of antibody treatment, confirming that treatment interfered with the disease process. Access of therapeutic anti-CD40 to potential sites of action, the secondary lymphoid organs and the brain white matter lesions, was visualized in situ. The present data are the first to demonstrate the clinical potential of blocking APC and effector cell functions using murine antagonist anti-CD40 mAb in the treatment of chronic inflammatory diseases.

Protection against experimental autoimmune encephalomyelitis by a proteasome modulator

The capacity of interferon β to alter the course of multiple sclerosis has promoted a new therapeutic concept, based upon the modulation of the immune response rather than its suppression. As the proteasome plays a crucial role in the control of the inflammatory process and immune cell survival, targeting the proteasome appears as a novel approach for the prevention and treatment of inflammatory autoimmune diseases. We have previously shown that ritonavir, an HIV-1 protease inhibitor used in AIDS therapy, can modulate the proteasome function by inhibiting the chymotrypsin-like activity and enhancing the trypsin-like activity. We have, therefore, explored its therapeutic potential on experimental autoimmune encephalomyelitis (EAE), an experimental model of multiple sclerosis, in Lewis rats and SJL mice. Daily administration of ritonavir during autoimmune antigen stimulation prevented clinical symptoms of EAE in a dose- and time-dependent manner. This protection was accompanied by an inhibition of the mononuclear cell infiltration into the central nervous system usually observed in EAE. Despite a complete absence of clinical symptoms during first EAE induction, ritonavir-treated animals became resistant to further induction of EAE, suggesting an immune mechanism of protection. These results suggest that proteasome modulation using ritonavir or analogues may be of interest for patients with multiple sclerosis.