Form Of Experimental Allergic Encephalomyelitis Research Articles

Evaluation of methods of modeling and formation of experimental allergic encephalomyelitis

Introduction: Experimental autoimmune (allergic) encephalomyelitis (EAE) induced by intradermal injection of ho­mogenate of the brain, spinal cord and peripheral nerve with Freund’s stimulator, refers to a true autoimmune disease of the nervous system.
 Materials and methods: Experimental studies were conducted on white nonlinear rats. To induce experimental aller­gic encephalomyelitis (EAE), homologous brain homogenates was used, which leads among other drugs (homologous, heterogeneous brain and spinal cord homogenates) by encephalitogenity. The connective tissue of the animal’s tail base was injected with a mixture of encephalitogenic suspension of 0.1 ml per 100 g of the body weight.
 Results and discussion: According to the results, in the rats, there was weight loss, and the abnormal neurological symptoms were found on an average of 10–12th days. Our experimental studies on the formation of EAE were con­firmed morphologically by electron microscopy.
 Conclusion: Thus, the use of this technique allowed us to obtain a simulated pathologic condition of multiple sclerosis in the form of experimental allergic encephalomyelitis and can be used in future studies to identify appropriate laws, the extent and nature of changes in the immune and nervous systems of the body when inducing experimental pathological conditions.

Ефективність моделювання експериментального алергічного енцефаломієліту як експериментальної моделі розсіяного склерозу

The purpose of the study was the most adequate modeling of multiple sclerosis in the form of autoimmune allergic encephalomyelitis for further use in the study of experimental equivalents of neurodegenerative conditions. Materials and methods. The article highlights the results of the formation of experimental allergic encephalomyelitis, for the induction of which homologous brain homogenates were used, which in terms of encephalitogenicity ranks first among other drugs (homologous, heterogeneous brain and spinal cord homogenates). An encephalitogenic mixture was injected into the connective tissue of the base of the animal's tail at the rate of 0.1 ml per 100 g of body weight. Results and discussion. Experimental allergic encephalomyelitis reproducible by intradermal administration of a homogenate of the brain, spinal cord and peripheral nerves with a Freund's stimulator belongs to a true autoimmune disease of the nervous system and is an experimentally reproducible model of multiple sclerosis. According to the experimental data obtained, the state of the animals showed that the rats of the experimental group lost body weight, had a number of pathological neurological symptoms, which manifested on average from 10-12 days. The increase in symptoms continued for an average of 7 days and was not very stable. Experimental animals had paresis, manifestations of ataxia, walking disorders and urinary and fecal incontinence, lethargy, which corresponded to 1-2 degrees of the rating scale in 13 animals. In 7 rats, paresis of the hind limbs and loss of tail tone were expressed (grade 3). Most of the rats recovered spontaneously within 6-8 days after the onset of clinical manifestations (18-20 days after immunization). According to the requirements of the experiment, during the paralytic stage, the rats had free access to food and water. In addition, our experimental studies on the formation of experimental allergic encephalomyelitis were confirmed morphologically using electron microscopy. Conclusion. The use of this technique for the formation of experimental allergic encephalomyelitis made it possible to obtain a simulated pathological state of multiple sclerosis in the form of experimental allergic encephalomyelitis and can be used in further studies to identify the corresponding patterns, the degree and nature of changes in the immune and nervous systems of the body during the reproduction of an experimental pathological state. The data obtained can serve as a basis for further studies of drugs and their combinations in order to improve and rationalize the pharmacotherapy of multiple sclerosis

Changes in Phospholipid Composition of the Spinal Cord in Rabbits with Allergic Encephalomyelitis as an Experimental Model of Multiple Sclerosis

Qualitative and quantitative composition of phospholipids in different compartments of the spinal cord was studied in normal rabbits and in experimental model of multiple sclerosis. The content of initial and final LPO products in compartments of the rabbit spinal cord was studied during different stages of the disease. The emergence of quantitative changes in the phospholipid composition depended on the form of experimental allergic encephalomyelitis and compartment of the spinal cord. The levels of conjugated dienes and MDA increased. The maximum levels of LPO products were recorded in the lumbar and sacral compartments of the spinal cord in severe experimental allergic encephalomyelitis.

Activation of p38 MAPK in CD4 T cells controls IL-17 production and autoimmune encephalomyelitis

AbstractAlthough several transcription factors have been shown to be critical for the induction and maintenance of IL-17 expression by CD4 Th cells, less is known about the role of nontranscriptional mechanisms. Here we show that the p38 MAPK signaling pathway is essential for in vitro and in vivo IL-17 production by regulating IL-17 synthesis in CD4 T cells through the activation of the eukaryotic translation initiation factor 4E/MAPK-interacting kinase (eIF-4E/MNK) pathway. We also show that p38 MAPK activation is required for the development and progression of both chronic and relapsing-remitting forms of experimental allergic encephalomyelitis (EAE), the principal autoimmune model of multiple sclerosis. Furthermore, we show that regulation of p38 MAPK activity specifically in T cells is sufficient to modulate EAE severity. Thus, mechanisms other than the regulation of gene expression also contribute to Th17 cell effector functions and, potentially, to the pathogenesis of other Th17 cell–mediated diseases.

Treatment of Mice with the Suppressor of Cytokine Signaling-1 Mimetic Peptide, Tyrosine Kinase Inhibitor Peptide, Prevents Development of the Acute Form of Experimental Allergic Encephalomyelitis and Induces Stable Remission in the Chronic Relapsing/Remitting Form

We have previously characterized a novel tyrosine kinase inhibitor peptide (Tkip) that is a mimetic of suppressor of cytokine signaling 1 (SOCS-1) and inhibits JAK2 phosphorylation of the transcription factor STAT1alpha. We show in this study that Tkip protects mice against experimental allergic encephalomyelitis (EAE), an animal model for multiple sclerosis. Mice are immunized with myelin basic protein (MBP) for induction of disease. Tkip (63 mug) administered every other day suppressed the development of acute EAE in 75% of New Zealand White (NZW) mice. Furthermore, Tkip completely protected SJL/J mice, which where induced to get the relapsing/remitting form of EAE, against relapses compared with control groups in which >70% of the mice relapsed after primary incidence of disease. Protection of mice by Tkip was similar to that seen with the type I IFN, IFN-tau. Protection of mice correlated with lower MBP Ab titers in Tkip-treated groups as well as suppression of MBP-induced proliferation of splenocytes taken from EAE-afflicted mice. Cessation of Tkip and IFN-tau administration resulted in SJL/J mice relapsing back into disease. Prolonged treatment of mice with Tkip produced no evidence of cellular toxicity or weight loss. Consistent with its JAK2 inhibitory function, Tkip also inhibited the activity of the inflammatory cytokine TNF-alpha, which uses the STAT1alpha transcription factor. The data presented in this study show that Tkip, like the type I IFN, IFN-tau, inhibits both the autoreactive cellular and humoral responses in EAE and ameliorates both the acute and chronic relapsing/remitting forms of EAE.

A1 adenosine receptor upregulation and activation attenuates neuroinflammation and demyelination in a model of multiple sclerosis.

The neuromodulator adenosine regulates immune activation and neuronal survival through specific G-protein-coupled receptors expressed on macrophages and neurons, including the A1 adenosine receptor (A1AR). Here we show that A1AR null (A1AR-/-) mice developed a severe progressive-relapsing form of experimental allergic encephalomyelitis (EAE) compared with their wild-type (A1AR+/+) littermates. Worsened demyelination, axonal injury, and enhanced activation of microglia/macrophages were observed in A1AR-/- animals. In addition, spinal cords from A1AR-/- mice demonstrated increased proinflammatory gene expression during EAE, whereas anti-inflammatory genes were suppressed compared with A1AR+/+ animals. Macrophages from A1AR-/- animals exhibited increased expression of the proinflammatory genes, interleukin-1beta, and matrix metalloproteinase-12 on immune activation when matched with A1AR+/+ control cells. A1AR-/- macrophage-derived soluble factors caused significant oligodendrocyte cytotoxicity compared with wild-type controls. The A1AR was downregulated in microglia in A1AR+/+ mice during EAE accompanied by neuroinflammation, which recapitulated findings in multiple sclerosis (MS) patients. Caffeine treatment augmented A1AR expression on microglia, with ensuing reduction of EAE severity, which was further enhanced by concomitant treatment with the A1AR agonist, adenosine amine congener. Thus, modulation of neuroinflammation by the A1AR represents a novel mechanism that provides new therapeutic opportunities for MS and other demyelinating diseases.

Epicutaneous Immunization with Autoantigenic Peptides Induces T Suppressor Cells that Prevent Experimental Allergic Encephalomyelitis

Information on how suppressor/regulatory T cells can be generated directly in vivo and prevent autoimmunity remains fragmentary. We show here that epicutaneous immunization (ECi) with the immunodominant peptide of myelin basic protein (MBP), Ac1-11, protects mice that are transgenic for an Ac1-11-specific T cell receptor against both the induced and spontaneous forms of experimental allergic encephalomyelitis (EAE). This protection was antigen specific and antigen dose dependent, and was mediated by CD4 +/CD25 − T cells whose suppressive activity required cell-cell contact and could transfer protection to naive recipients. These ECi-induced suppressor T cells controlled naive MBP-specific CD4 T cells by inhibiting both their activation and their capacity to secrete IFN-γ. There was no CD4 T cell infiltration in the brain of protected mice. Finally, ECi with autoantigenic peptides protected two nontransgenic models from relapsing-remitting EAE in an antigen-specific and antigen dose-dependent manner.

Experimental allergic encephalomyelitis in the New World monkey Callithrix jacchus.

Models that adequately reflect the complexity of human multiple sclerosis (MS) are needed, especially for preclinical testing of immunomodulatory drugs. Our group has created a unique experimental system in a New World outbred primate, the common marmoset Callithrix jacchus (C. jacchus). Following immunization with myelin, these monkeys develop a chronic, relapsing-remitting form of experimental allergic encephalomyelitis (EAE), which pathologically recapitulates the hallmark features of lesions of human MS. The MS-like lesion in C. jacchus results from a complex immune response against myelin antigens and requires both T cells and pathogenic antibodies. Studies of C. jacchus EAE have permitted the identification of a major target for pathogenic autoantibodies in MS, the myelin/oligodendrocyte glycoprotein. Other advantages of the model include a natural bone-marrow chimerism, which permits T-cell adoptive transfers between siblings, and the possibility of using different antigens to produce either inflammatory or demyelinating phenotypes of EAE. Despite their small size, sequential in vivo imaging and immunological studies are possible in these monkeys, and have been used to monitor efficacy in preclinical trials. Due to close phylogeny and high homology of immune and nervous system genes with humans, this model should fast-track the development of novel therapeutics for MS.

Genetic influence on disease course and cytokine response in relapsing experimental allergic encephalomyelitis.

A protracted and relapsing form of experimental allergic encephalomyelitis (EAE) develops in the DA rat after immunization with rat spinal cord homogenate (SCH) emulsified in incomplete Freund's adjuvant (IFA). The genetic influence on this model has been analyzed by immunizing MHC congenic strains on both LEW and DA genetic backgrounds, and recombinant inbred strains between DA and E3 rats. An in situ hybridization assay was used to examine the expression of mRNA for IFN-gamma, IL-4, IL-10 and transforming growth factor (TGF)-beta both in sections of spinal cords and the antigen-induced expression for these cytokines by splenocytes after in vitro stimulation with encephalitogenic MBP peptides. The susceptibility of relapsing EAE after immunization with SCH in IFA in the DA strain, but not the E3 strain, was correlated with a lack of expression for TGF-beta in the spinal cord. The recombinant inbred DXEB rats developed a severe EAE while surprisingly no signs of disease were observed in the DXEA strain, which shares the MHC region with the DXEB strain, after immunization with the MBP 63-87 peptide. Resistance to relapsing EAE in the DXEA strain correlated with increased non-MHC controlled expression for TGF-beta and lack of IFN-gamma in the spinal cord. The same pattern of cytokine expression was seen in splenocytes after stimulation in vitro with the MBP 63-87 peptide. A spreading of the immune response to the MBP 87-110 peptide was seen. Non-MHC genes controlled the quality of this response: splenocytes from MBP 63-87 immunized DXEB rats responded in vitro towards the MBP 87-110 peptide by expressing mRNA for IFN-gamma, IL-10 and IL-4, whereas in the DXEA strain the corresponding response involved IL-4 and TGF-beta. Taken together these data show that non-MHC controlled expression of mRNA for TGF-beta is associated with resistance to EAE.

Inhibition of allergic encephalomyelitis in marmosets by vaccination with recombinant vaccinia virus encoding for myelin basic protein

A primary demyelinating form of experimental allergic encephalomyelitis (EAE) resembling human multiple sclerosis (MS) occurs in Callithrix jacchus marmosets following immunization with human white matter. Participation of a T-cell immune response against myelin basic protein (MBP) in this disease model is supported by observations of increased reactivity against MBP in PBMC and of adoptive transfer of an inflammatory form of EAE by MBP-reactive T-cells. To evaluate the effects of ectopic presentation of MBP on marmoset EAE, animals were vaccinated prior to induction of EAE by subcutaneous injection of attenuated strains of vaccinia virus genetically engineered to contain either the entire coding sequence for human MBP (vT15) or the equine herpes virus glycoprotein gH gene (vAbT249). Vaccination with vT15 was followed by transient cytoplasmic and surface membrane expression of MBP in circulating PBMC (15–45 days). The onset of clinical EAE after immunization (pi) was markedly delayed in vT15-vaccinated animals (37–97 days pi, n=4) compared to vAbT249-vaccinated controls (14–18 days pi, n=3). Proliferative responses against MBP but not against vaccinia antigens or phytohemagglutinin were suppressed in protected animals. Thus, development of attenuated live viruses carrying genes for myelin antigens could be useful for induction of immunologic tolerance and for modulation of autoimmune demyelination.

Oral feeding of interferon τ can prevent the acute and chronic relapsing forms of experimental allergic encephalomyelitis

IFN τ is a member of the type I IFN family but unlike IFN α and IFN β, IFN τ lacks toxicity at high concentrations. Recently, ovine IFN τ was shown to prevent acute induction and superantigen reactivation of experimental allergic encephalomyelitis (EAE), an animal model for multiple sclerosis (MS). In this report, we examined the ability of IFN τ when administered by oral feeding to block development of EAE. Oral feeding of IFN τ prevented paralysis in the acute form of EAE in NZW mice and chronic-relapsing EAE in SJL/J mice. In addition, oral feeding of IFN τ at 10 5 U/dose was as effective as intraperitoneal (i.p.) injection in preventing chronic-relapsing EAE, and both forms of IFN τ administration resulted in IL10 production. Histological examination revealed no inflammatory lymphocytic infiltration to the CNS in IFN τ treated animals as compared to controls. Prolonged treatment of IFN τ was shown to be necessary for chronic-relapsing EAE since removal of IFN τ treatment by either oral feeding or i.p. injection resulted in onset of disease. Lastly, sera from SJL/J mice which received prolonged IFN τ treatment by oral feeding exhibited little to no development of anti-IFN τ antibodies. Thus, oral feeding of ovine IFN τ may be a successful form of IFN τ administration for treatment of autoimmune diseases such as MS and may circumvent potentially debilitative antibody responses.

Antibody facilitation of multiple sclerosis-like lesions in a nonhuman primate.

In the human disease multiple sclerosis (MS), the immune mechanisms responsible for selective destruction of central nervous system myelin are unknown. In the common marmoset Callithrix jacchus, a unique demyelinating form of experimental allergic encephalomyelitis resembling MS can be induced by immunization with whole myelin. Here we show that the MS-like lesion can be reproduced by immunization against the extracellular domain of a single myelin protein, myelin/oligodendrocyte glycoprotein (MOG). By contrast, immunization against the quantitatively major myelin proteins myelin basic protein or proteolipid protein results in inflammation but little or no demyelination. Furthermore, in the presence of encephalitogenic (e.g., disease-inducing) T cells, the fully demyelinated lesion is reconstructed by systemic administration of IgG purified from whole myelin-, or MOG-immunized animals, and equally by a monoclonal antibody against MOG, but not by control IgG. Encephalitogenic T cells may contribute to the MS-like lesion through disruption of the blood-brain barrier that permits access of demyelinating antibody into the nervous system. The identification of MOG as a major target antigen for autoimmune demyelination in a nonhuman primate should facilitate development of specific immunotherapies for human MS.

Gadolinium enhancement in acute and chronic-progressive experimental allergic encephalomyelitis in the guinea pig.

Magnetic resonance imaging detects blood-brain barrier disruption after gadolinium-DTPA enhancement of central nervous system lesions of multiple sclerosis. Experimental allergic encephalomyelitis has many clinical and pathological features in common with multiple sclerosis including alterations in the integrity of the blood-brain barrier. We have compared T2-weighted cranial MR images with Gd-DTPA dimeglumine-enhanced T1-weighted images of myelin basic protein-induced acute (Days 8-42 postimmunization) and central nervous system-induced chronic-progressive (Days 70-95 postimmunization) forms of experimental allergic encephalomyelitis in the guinea pig. Although animals from both groups had abnormal T2-weighted images, only the myelin basic protein-acute-EAE animals (Days 14-24 postimmunization) showed enhancement on postcontrast MR studies. The different responses of the acute and chronic diseases may result from different immunogens, severity of disease, or different permeability of the blood-brain barrier. Therefore, gadolinium-DTPA-enhanced, T1-weighted MR images distinguish acutely active and chronic inflammatory lesions in experimental allergic encephalomyelitis.

Monoclonal anti-gamma interferon antibodies enhance experimental allergic encephalomyelitis.

Interferon-gamma (IFN-gamma) is a cytokine with multiple activities on a variety of cells. Under various circumstances, IFN-gamma can exhibit either pro-inflammatory or inhibitory actions. Treatment of SJL/J mice with a monoclonal antibody (Mab) to IFN-gamma during the afferent limb of the immune response to myelin protein produced an enhancement of acute experimental allergic encephalomyelitis (EAE), with increased morbidity, mortality and earlier onset of disease. Systemic administration of IFN-gamma did not improve or worsen clinical outcome, but delayed disease onset. Passive transfer of immune lymph node cells co-activated with MBP and anti-IFN-gamma Mab resulted in more sever disease than that induced by MBP stimulated cells or MBP and IFN-gamma co-stimulated cells. However, in vitro proliferation of an MBP specific T cell line was not influenced by IFN-gamma nor anti-IFN-gamma treatment. Mab to IFN-gamma inhibited suppressor function, in a non-specific assay. These in vivo and in vitro results suggest that systemic IFN-gamma serves as a physiological regulator of a suppressor mechanism in EAE. The abrogation of this regulatory mechanism by anti-IFN-gamma administration contributes to a more severe form of experimental allergic encephalomyelitis.

Concordance and localization of maximal vascular permeability change and fibrin deposition in the central neuraxis of Lewis rats with cell-transferred experimental allergic encephalomyelitis.

This study utilized Lewis rats and the cell-transfer form of experimental allergic encephalomyelitis (EAE) to focus on two central nervous system microvascular alterations known to be intimately associated with early clinical neurological signs of the disease, namely increased vascular permeability and deposition of fibrin. The main objective of the work was to define the degree of concordance and the anatomical localization of maximal vascular permeability change and fibrin deposition within the neuraxis of recipient rats during the earliest expression of clinical manifestations of the disease. Recipients were injected with predetermined doses of activated, myelin basic protein (MBP)-reactive syngeneic donor lymphoid cells and killed 6 or 7 days later when they exhibited the first clinical signs of disease. This experimental design allowed assessment of late occurring immune activities of a single population of MBP-reactive effector cells. Increased vascular permeability, expressed as mean extravascular blood equivalents (EVBE), attained maximum change, i.e., 16.04 +/- 5.07, within the lumbosacrococcygeal segment of the spinal cord (LSC). Maximal density of fibrin depositions, i.e., 192 +/- 94 deposits, also occurred within the LSC cord. The concordance of these two histoimmunopathological events, their tight linkage to early clinical signs of disease and the fact that both events attained maximal values within the LSC cord suggest that increased permeability and activation of the coagulation cascade may be prerequisite events for the expression of neurological signs of EAE.

Inhibition of experimental allergic encephalomyelites by lithium chloride: specific effect or nonspecific stress?

Intraperitoneal injections of lithium chloride inhibited development of experimental allergic encephalomyelitis (EAE) in rats. The degree of inhibition was inversely related to the intensity ofthe immunologic stimulation, which depended on the choice of adjuvant. High dosage of lithium, the intraperitoneal route, and an intermittent schedule of administration were required to achieve suppression of EAE. This suggested that the immunosuppression was a toxic effect, mediated, at least in part, through the hypothalamic-pituitary-adrenal cortex axis. This hypothesis was supported by evidence that the lithium treatment schedule, especially the intermittent schedule, had caused adrenal cortical activation with thymolysis in intact rats and that it was lethal to adrenalectomized rats. Lithium also inhibited EAE produced by adoptive immunization, thus implicating the efferent arm of the immune response. A single dose of lithium was effective in this form of EAE, even in adrenalectomized rats. Therefore lithium affects EAE by both specific immunosuppressive and nonspecific adrenocortical-dependent mechanisms.

Apoptosis in the nervous system in experimental allergic encephalomyelitis

We report here for the first time the occurrence of apoptosis of cells in the spinal cord in experimental allergic encephalomyelitis (EAE), an autoimmune, T-cell-mediated demyelinating disease. Four different forms of EAE were studied in the Lewis rat: (i) acute EAE induced by inoculation with whole spinal cord and adjuvants; (ii) acute EAE induced by inoculation with myelin basic protein (MBP) and adjuvants; (iii) acute EAE induced by the passive transfer of MBP-sensitized spleen cells; (iv) chronic relapsing EAE induced by inoculation with whole spinal cord and adjuvants followed by treatment with low-dose cyclosporin A. Cells undergoing apoptosis were recognized at light and electron microscopy by the presence of either crescentic masses of condensed chromatin lying against the nuclear envelope or rounded masses of uniformly dense chromatin. They were found in both the white and grey matter of the spinal cord in all 4 forms of this disease. Although it was not possible to identify definitively the types of cells undergoing apoptosis, the size and location of some of the affected cells suggested that they were oligodendrocytes. As there is now a large body of evidence that T-cell-induced target cell death takes the form of apoptosis, it is attractive to hypothesize that oligodendrocyte apoptosis is occurring in EAE as a result of oligodendrocyte-directed T-cell cytotoxicity. However, other apoptotic cells were located within the myelin sheath, meninges and perivascular spaces and were clearly not oligodendrocytes but were most likely blood-derived mononuclear cells. The sparsity of their cytoplasm and the absence of phagocytosed material suggested that they were mainly lymphocytes rather than macrophages. Apoptosis has been shown to be involved in deleting autoreactive T-cells during the normal development of tolerance. Thus apoptotic deletion of myelin/oligodendrocyte-specific lymphocytes in the central nervous system in EAE might explain both the subsidence of inflammation and the acquisition of tolerance in this autoimmune disease.

Identification of an encephalitogenic determinant of myelin proteolipid protein for the rabbit

A late onset, demyelinating form of experimental allergic encephalomyelitis (EAE) was induced in New Zealand White rabbits following immunisation with a synthetic peptide representing the amino acid sequence 91–110 of bovine myelin proteolipid protein (PLP). Histologically, disease was associated with varying degrees of central nervous system (CNS) inflammation, which in six of seven animals was accompanied by axonal degeneration and secondary demyelination. Primary demyelination with axonal sparing was generally absent in this model EAE. Immunohistochemical and immunoelectron microscopic analysis of CNS tissue indicate that B cell epitopes within this encephalitogenic PLP sequence are not exposed at the surface of the myelin sheath, but are sequestered within compact multilamellar myelin. Furthermore, no correlation was observed between the anti-PLP antibody titer induced by the peptide and either the clinical severity or histopathology of the disease. These observations suggest that the B cell response to epitopes within the PLP sequence 91–110 does not play a primary role in the immunopathogenesis of PLP-induced EAE.

An improved radioimmunoassay for myelin basic protein-like immunoreactive material in cerebrospinal fluid

A modified radioimmunoassay protocol is described which can measure elevated levels of myelin basic protein-like immunoreactive material in the cerebrospinal fluid of some patients with multiple sclerosis or head injury and in rats developing an acute demyelinating form of experimental allergic encephalomyelitis. The assay uses synthetic peptides that differ in their sequences from natural myelin basic protein for both standard and radioligand, but in apparent contrast to previously published assays serial dilutions of samples produce the expected dose estimates when interpolated from the standard curve. A second radioimmunoassay was produced with high sensitivity and specificity for myelin basic protein peptides with a carboxyl terminus at phenylalanine 89. This assay was used in attempts to detect the myelin basic protein-like immunoreactivity recently reported to occur in human urine. This radioimmunoassay failed to detect specific immunoreactivity in urine samples from control and multiple sclerosis donors. The specificities of both assays were studied using a wide range of synthetic peptides and the importance of this information to the design of future assays is addressed. Our work reinforces that of others in suggesting the complex situation involved in the design of assays for MBP fragments in body fluids. We are willing to distribute the reagents for use in our CSF assay to researchers who request them.

NMR studies in the relapsing experimental allergic encephalomyelitis (EAE) model of multiple sclerosis in the strain 13 guinea pig

Juvenile strain 13 guinea pigs sensitized with an emulsion of whole isologous central nervous system (CNS) tissue in complete Freund's adjuvant in the first two weeks of life develop a relapsing-remitting form of experimental allergic encephalomyelitis (EAE) which resembles multiple sclerosis (MS) both clinically and pathologically. In order to determine if this experimental model could be used to identify the tissue factors which contribute to the magnetic resonance imaging (MRI)-detected lesions in MS, we measured T 1 and T 2 relaxation times, tissue specific gravity and histology throughout the entire CNS in vitro in eighteen animals during the acute phase (first attack), and twenty-one animals during further periods of clinical worsening (relapses) and recovery (remissions). The neuropathological findings of spinal cord meningeal inflammation, perivascular and parenchymal infiltration (myelitis and encephalitis) and demyelination were more marked during periods of clinical worsening than when the animal had recovered clinically. Even though the histological changes of EAE were present in all experimental animals, NMR relaxation times and tissue specific gravity could not distinguish experimental (first attack, subsequent relapses and remissions) from control animals due to a wide range of values for each of these parameters. Although relapsing EAE in the strain 13 guinea pig has been an instructive model of MS, we have found that in vitro NMR relaxometry cannot be used to predict the presence or degree of pathological change in the nervous system of these experimental animals.