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Hyperacute experimental allergic encephalomyelitis in rhesus monkeys as a model of acute necrotizing hemorrhagic encephalomyelitis.

A comparative study of clinical and morphological findings in three fatal cases of acute necrotizing hemorrhagic encephalomyelitis (ANHE) and hyperacute experimental allergic encephalomyelitis (HEAE) in rhesus monkeys is reported. In all cases ANHE was characterized clinically by definite prodromal respiratory infection. The course was rapidly progressive with fatal termination. The salient histopathological changes were necrosis of blood vessels with plasma exudation and fibrin impregnation, hemorrhages and inflammatory reaction in the damaged cerebral tissue. Perivascular lymphoid histiocytic infiltration with glial proliferation was also noted in all cases. Numerous compound granular cells were found in one case. HEAE was detected in five rhesus monkeys immunized with homological spinal cord emulsion with complete Freund adjuvant. The illness was acute or subacute and the course was rapidly progressive with a fatal end. There was multiple necrosis of small blood vessels with plasma exudation, fibrin impregnation and massive neutrophila infiltration of the damaged brain tissue in all rhesus monkeys with HEAE. There was also widespread glial proliferation and numerous compound granular cells alongside with necrosis of blood vessels in the brain. These findings suggest that HEAE in rhesus monkeys can be viewed as an adequate model of ANHE.

Adolescent

Host genetic regulation of acute MHV-4 viral encephalomyelitis and acute experimental autoimmune encephalomyelitis in (BALB/cKe x SJL/J) recombinant-inbred mice.

In the present report we provide the strain distribution patterns of susceptibility to acute mouse hepatitis virus type-4 (MHV-4) encephalomyelitis, acute experimental allergic encephalomyelitis (EAE) and vasoactive amine sensitivity (VAAS) for 9 (CXJ) recombinant-inbred strains between BALB/cKe (C) and SJL/J(J) mice. We confirm that susceptibility to MHV-4 is not linked to the H-2 complex, and that all strains susceptible to acute EAE have both a responder H-2 haplotype (H-2s or H-2d) and induced (B. pertussis) VAAS. In addition, we provide evidence that susceptibility to acute EAE induction is controlled by an additional presently unmapped locus and that an EAE-like histopathological disease does not usually follow MHV-4 infection intracerebrally in animals susceptible to MHV-4, acute EAE and induced VAAS.

Animals

Monoclonal antibody to Theiler's murine encephalomyelitis virus defines a determinant on myelin and oligodendrocytes, and augments demyelination in experimental allergic encephalomyelitis.

Theiler's murine encephalomyelitis virus (TMEV) causes a chronic demyelinating disease in mice. The mechanisms underlying the demyelination have not been fully elucidated. We have raised a mAb to TMEV (DA strain), H8, that reacts both with TMEV VP-1 and galactocerebroside (GC). In mouse brain cultures, cells positive for the mAb H8 epitope were double labeled with antibody to myelin basic protein, indicating that those cells were oligodendrocytes. Further, mAb H8 could immunostain myelin structures in frozen sections from mouse brains. When injected intravenously into mice with acute allergic encephalomyelitis, mAb H8 increased by 10-fold the size of demyelinated areas within the spinal cords. This is the first report demonstrating that an antibody to virus can enhance demyelination of a central nervous system disease. Ig fractions from the sera of mice with chronic TMEV infection had antibody(s) to GC, as well as to TMEV, as determined by ELISA. Furthermore, a competition ELISA for TMEV or GC antigen revealed that sera from these infected mice contained antibody(s) with the same specificity as mAb H8. Our results indicate that antibodies generated by immune response to TMEV can react with myelin and oligodendrocytes, and contribute to demyelination through an immune process.

Animals

Porcine encephalomyelitis caused by hemagglutinating encephalomyelitis virus.

Six epizootics of encephalomyeltis in suckling pigs in Minnesota were attributed to infection with hemagglutinating encephalomyelitis virus. The disease occurred in 74 litters of pigs and was characterized by sudden onset of tremors, inappetence, weakness, atazia, and hyperesthesia, with high morbidity and case fatality rate. Pathologic changes consisted of marked nonsuppurative, nondemyelinating encephalomyelitis characterized by perivascular mononuclear cuffing, gliosis, neuronal death, and satellitosis. Clinical disease was limited principally to suckling pigs during a single farrowing period and did not recur in the herds involved during the ensuing 18 months.

Animals

Anti-synaptic antibody in allergic encephalomyelitis. II. The synapse-blocking effects in tissue culture of demyelinating sera from experimental allergic encephalomyelitis.

It has been suggested that demyelination cannot account for all of the observed clinical symptoms of multiple sclerosis (MS), in particular the rapidity of onset and remission of the disease, and attention has been focussed on the role of the synapse in 'demyelinating diseases'. In the present paper we have attempted to resolve the fundamental question of the site of action of a demyelinating disease, experimental allergic encephalomyelitis (EAE), by the use of cultures of neonatal rat cerebellum. Electrophysiological and morphological development in these cultures run hand-in-hand, and in the first few days in vitro there is a 4-5 day period when synapses are both seen ultrastructurally and known to be functioning but before the onset of myelination. The serum from guinea pigs with EAE was added to these cultures at different stages during their development and the morphological and electrophysiological effects observed. An abolitionary effect on the bioelectric activity of the culture was only observed when the serum was added to mature, myelinated cultures. Also the same active sera had no effect on synaptic activity before myelination had occurred. We conclude that the synaptic blocking effect occurs only when myelin is destroyed.

Animals

Subtle encephalomyelitis in children: a variant of acute disseminated encephalomyelitis.

Four children with chronic, mild, nonspecific symptoms are described in whom magnetic resonance imaging (MRI) showed the presence of multifocal white-matter lesions suggestive of acute disseminated encephalomyelitis. The children ranged in age from 14 months to 15 years. The clinical picture was vague and inconclusive and consisted of several months of headaches, irritability, clumsiness, and personality change. Physical examinations were noncontributory. Laboratory investigation revealed no other cause of the demyelination. All of the patients have done well without any treatment, with a disappearance of symptomatology. The white-matter lesions on MRI scan in these children may indicate subtle exposure to a myelinolytic antigen. It has been suggested that such an exposure may create a state of complete or partial resistance to the encephalitogenic potential of the next infection or immunization. With complete resistance, the patient remains healthy and with partial resistance progressive demyelination results. Verification of these findings by others would suggest a possible benefit of a multicenter study of such patients, with virological, HLA testing, and long-term follow-up, in understanding the etiopathogenesis of multiple sclerosis.

Acute Disease

[Correlation of heredity and environmental factors in the etiology of Vilyui encephalomyelitis. II. A population genetic study in districts of Vilyui encephalomyelitis distribution].

Population-genetic investigation was carried out in the regions endemic for Viljuisk encephalomyelitis (VE). The following indices were estimated: the relationship coefficient, the inbreeding coefficient, the intensity of migration, genetic structure of the population. The aim of the investigation was to explain causes of intrapopulational and, in some cases, of intragenus accumulation of the VE patients. No evidence of isolation or increased inbreeding were found in highly affected populations. The genetic structure of a group of VE patients tested for 9 polymorphic systems did not reveal any deviation from the control group. Several VE cases in healthy populations occured in some years after the immigration of a VE patient. These data confirm the hypothesis that VE is transmitted from a VE patient to healthy persons. Among these persons fall ill those who have a hereditary determined increased sensitivity to VE which results in intrapopulation and intragenus accumulation of VE cases.

Adult

[Experimental allergic encephalomyelitis as a model for the study of therapeutic concepts for encephalomyelitis disseminata].

The induction of immunological tolerance with, and for, the caused organotypical antigen is a conception for a specific therapy for neuroimmunological diseases with at least a partial autoallergic pathogenesis. Appropriate to a set step-by-step programme for the development of antigen-specific therapy preventive tolerance experiments were carried out at the model of experimental allergic encephalomyelitis (EAEM) with allogenic myelin basic protein (BP) prepared from rabbits. The result is: 100 ug BP given intravenously simultaneously with 100 ug BP in incomplete Freud's adjuvant given intracutanously twice a week and 40 mg Cyclophosphamid given daily during the minor clinical incidence rate and no signs of EAEM pathomorphologically. A longlasting tolerance for the BP could be obtained as a test proved after 100 days. Hints are given for further potential therapeutic treatments, such as the use of antigen bound chemically to the immunosuppressive drug or the use of chemically modified BP for the induction of a specific tolerance.

Animals

The role of prolactin in autoimmune demyelination: suppression of experimental allergic encephalomyelitis by bromocriptine.

Several lines of evidence suggest that the anterior pituitary hormone prolactin has a stimulatory role on immune function and that pharmacological suppression of prolactin secretion with the dopamine-agonist bromocriptine suppresses both humoral and cellular immunity. Here, we describe the effects of prolactin-suppression on the course of experimental allergic encephalomyelitis in female Lewis rats. Initiation of continuous bromocriptine treatment before immunization reduced both the severity and incidence of clinical signs of acute experimental allergic encephalomyelitis. Experimental allergic encephalomyelitis-immunized rats experienced a threefold rise in basal prolactin levels on day 4 after immunization and maintained elevated prolactin levels on day 10, before the onset of neurological signs of experimental allergic encephalomyelitis. Bromocriptine treatment reduced prolactin levels to those of sham-immunized rats. In vivo bromocriptine pretreatment inhibited splenic lymphocyte proliferative responses in vitro to the immunizing antigen and to concanavalin A. Moreover, bromocriptine therapy was protective when initiated 1 week after the initial immunization and was also effective in suppression of late disease. These results indicate that (1) prolactin levels are elevated after immunization and before the onset of experimental allergic encephalomyelitis, (2) bromocriptine inhibits both prolactin secretion and the severity of acute experimental allergic encephalomyelitis, and (3) inhibition is also present when treatment is begun after sensitization, suggesting an effect of prolactin on the effector limb of the immune response during experimental allergic encephalomyelitis.

Animals

Histocompatibility determinants in childhood postinfectious encephalomyelitis.

Postinfectious encephalomyelitis and multiple sclerosis have clinical, immunologic, and neuroradiographic similarities. We studied HLA determinants in six white children consecutively diagnosed with postinfectious encephalomyelitis. Each of the children had HLA determinants which have been associated with multiple sclerosis. Relative risk (RR) calculations demonstrated that these antigens and genotypes occurred significantly more often in patients with postinfectious encephalomyelitis than in the control population (A3, RR 6.14; B7, RR 6.14; DR2, RR 4.51; A3B7, RR 9.36; A3DR2, RR 5.83; B7DR2, RR 6.13; A3B7DR2, RR 10.90). These data suggest that children with postinfectious encephalomyelitis are genetically predisposed to this demyelinating disease. Although the same HLA determinants were found in these patients as in those with multiple sclerosis, studies of a larger number of postinfectious encephalomyelitis patients will be needed before it can be concluded that the two diseases share a common genetic propensity.

Child

Cross-protective immunity between equine encephalomyelitis viruses in equids.

Eighteen equids were inoculated with eastern equine encephalomyelitis (EEE) and 18 equids with western equine encephalomyelitis (WEE) viruses to produce EEE virus- and WEE virus-immunized equids. Twelve surviving EEE virus-seropositive equids, 15 surviving WEE virus-seropositive equids, and 10 nonimmunized, seronegative equids (controls) were subsequently inoculated with an equine pathogenic (epizootic) strain of Venezuelan equine encephalomyelitis (VEE) virus to determine cross-protective immunity. Challenge infection produced 90% mortality in control (nonimmunized) equids, and 40% mortality in WEE virus-seropositive equids; all EEE virus-seropositive equids survived. Postchallenge exposure VEE viremia levels in EEE virus- or WEE virus-seropositive equids were lower than those in the 10 nonimmunized VEE virus-inoculated control equids. Plaque-neutralizing antibody responses to VEE virus in the EEE virus- and WEE virus-seropositive equids were similar in time of onset and titer to the antibody responses of nonimmunized equids. Neutralizing antibody to the third equine encephalomyelitis virus (either EEE virus or WEE virus) was detectable in 19 of 27 equids after inoculation with the challenge virus, VEE. Demonstration of cross-protective immunity between EEE or WEE virus and VEE virus in equids confirmed field observations made during the VEE epizootic in Texas in 1971.

Alphavirus

[Hyperacute encephalomyelitis following lyssa vaccination].

UNLABELLED: A case of hyperacute disseminated encephalomyelitis following lyssa-vaccination is reported. Clinical symptoms occurred on the tenth day after the vaccination and the patient died three days afterward. Demyelinization and glia proliferation was observed histologically in the spinal cord. No alterations could be seen in the peripheric nerves. CONCLUSIONS: 1. The spinal and cerebral forms of the postvaccinial encephalomyelitis can not be sharply distinguished. 2. In the postvaccinial encephalomyelitis there are also severe infiltration, demyelinization and gliosis in the opticus. 3. Post-vaccinial lyssa encephalomyelitis is a rare, but unavoidable complication of the lassa-vaccination. 4. The State Insurance Company have to pay damages.

Acute Disease

Suppression of experimental autoimmune encephalomyelitis by oral administration of myelin antigens: IV. Suppression of chronic relapsing disease in the Lewis rat and strain 13 guinea pig.

Oral administration of proteins is a long-recognized method of inducing antigen-specific peripheral immune tolerance. We previously showed that oral administration of myelin basic protein suppresses monophasic experimental autoimmune encephalomyelitis in the Lewis rat when it is given in association with immunization and prior to disease onset. As a potential therapy for human autoimmune disease, it is crucial to determine whether oral tolerance can ameliorate an ongoing immune response. We therefore asked whether oral administration of myelin antigens, after sensitization and disease expression has occurred, could affect immunological, clinical, or pathological features of experimental autoimmune encephalomyelitis. Chronic relapsing experimental autoimmune encephalomyelitis was induced in the Lewis rat and strain 13 guinea pig by immunization with whole guinea pig cord homogenate, complete Freund's adjuvant, and Mycobacterium tuberculosis. Following recovery from the first attack, animals were orally given bovine myelin, guinea pig myelin, or guinea pig myelin basic protein three times per week for up to 3 months. Animals receiving myelin products orally had decreased severity and frequency of clinical relapses, decreased delayed-type hypersensitivity responses to myelin antigens, diminished inflammation in the central nervous system (CNS), and decreased areas of CNS demyelination. In the rat, guinea pig myelin basic protein was as effective as guinea pig myelin in ameliorating the disease and also resulted in decreased serum anti-myelin basic protein antibody levels. No exacerbation of disease or worsening of pathological findings occurred in the animals given myelin products. These results demonstrate that oral administration of myelin antigens can suppress chronic relapsing experimental autoimmune encephalomyelitis and have direct relevance to therapy of human demyelinating disorders such as multiple sclerosis.

Administration, Oral

T-cell receptor peptide immunization leads to enhanced and chronic experimental allergic encephalomyelitis.

It has previously been reported that synthetic peptides corresponding to sequences derived from T-cell receptor variable regions identified as dominant in the T-cell-mediated autoimmune disease experimental allergic encephalomyelitis in both the mouse and the rat can down-regulate disease in Lewis rats. In contrast to these results, we have found that immunization of Lewis rats with such peptides in complete Freund's adjuvant prior to induction of experimental allergic encephalomyelitis with myelin basic protein leads to responses ranging from profound disease enhancement to lack of disease. In some cases, enhanced disease was followed by a prolonged neurologic deficit that resembles multiple sclerosis more closely than does acute experimental allergic encephalomyelitis. These findings, on the one hand, support previous results showing T-cell receptor peptide-induced modulation of the disease experimental allergic encephalomyelitis and, on the other, indicate that such immunization is not a reliable method for inducing suppression of encephalitogenic effector cells.

Amino Acid Sequence

The pathogenesis of acute viral encephalitis and postinfectious encephalomyelitis.

Japanese encephalitis and postmeasles encephalomyelitis represent two important forms of acute encephalitis in the developing world. Japanese encephalitis accounts for 20,000 acute illnesses per year, and measles encephalomyelitis accounts for as many as 100,000. Both are accompanied by mortalities of 20%-30%, and in both forms, approximately one-half of the survivors have neurological sequelae. Therefore, these two diseases are responsible for a considerable proportion of worldwide mental and motor disabilities. Furthermore, both diseases are preventable with use of safe vaccines. Despite these similarities, their very different pathologies appear to be based on different mechanisms of pathogenesis (table 2). In Japanese encephalitis there is direct invasion of the virus into the nervous system, selective infection and destruction of neurons, and evidence that both humoral and cellular immune responses attenuate the infection. In measles encephalomyelitis there is little evidence that the virus invades the nervous system. Rather, measles virus infects lymphoid cells and causes abnormalities in immune regulation. Humoral immune responses are not found within the nervous system, and the cellular immune response may be inappropriately directed against host antigens. In measles encephalomyelitis, the inflammatory cells entering the nervous system may be the effector cells of autoimmune disease.

Animals

Anti-myelin basic protein antibody in experimental allergic optic neuritis and encephalomyelitis.

We produced demyelinating optic neuritis and encephalomyelitis in juvenile strain 13 guinea pigs by sensitization with optic nerve myelin. Three distinct clinical courses were noted: a severe, acute optic neuritis associated with a rapidly fatal encephalomyelitis; a mild, chronic optic neuritis with a nonfatal encephalomyelitis; and an initially mild disease followed by an acute exacerbation of optic neuritis and fatal encephalomyelitis. Clinically mild disease was associated with elevated levels of anti-myelin basic protein antibody, while severe disease was associated with extremely low antibody levels.

Animals

Comparative analysis of coronavirus JHM-induced demyelinating encephalomyelitis in Lewis and Brown Norway rats.

Lewis and Brown Norway rats were infected at different ages with the neurotropic murine coronavirus strain, JHM and the resultant central nervous system diseases were studied. Suckling rats of both strains came down with a fatal, acute encephalomyelitis. Weanling Lewis rats developed a subacute demyelinating encephalomyelitis which neuropathologically revealed changes of an immunopathologic reaction. In contrast, Brown Norway rats developed a clinically silent subacute demyelinating encephalomyelitis with a persistent JHM virus infection which was less severe and quite different from the subacute demyelinating encephalomyelitis in Lewis rats with respect to size, distribution, and localization of the demyelinating plaques as well as the type of infiltrating cells. In addition, infected Lewis rats showed a pronounced lymphocyte proliferation to myelin basic protein and JHM virus whereas lymphocytes from infected Brown Norway rats did not react to these two antigens. These observations demonstrate the pathogenetic importance of host factors in the development of virus-induced demyelination.

Aging

Nondiscocytic erythrocytes in myalgic encephalomyelitis.

Blood samples from 102 volunteers who believed they suffered from myalgic encephalomyelitis were photographed in a scanning electron microscope at 500x. All identifiable cells were counted and classified on the basis of their shape. The frequency of each cell shape was expressed as a percentage of the total number of cells counted in the sample. The resulting data were compared with that from 52 healthy controls and 99 cases of multiple sclerosis which had been selected randomly by a computer from a panel of 229 cases in a concurrent study. Samples from subjects with myalgic encephalomyelitis had the lowest percentages of normal red cells and the highest incidence of cup forms. The results provide evidence that myalgic encephalomyelitis has an organic cause. Quantitative analysis of red cell shape may assist in the diagnosis of myalgic encephalomyelitis.

Adolescent