Effect of encephalitogenic protein on migration in agarose of leukocytes from patients with multiple sclerosis. Variable effect of the antigen in a large dose range, with a literature review

Immunomodulatory Effect of Toll-Like Receptor-3 Ligand Poly I:C on Cortical Spreading Depression

The release of inflammatory mediators following cortical spreading depression (CSD) is suggested to play a role in pathophysiology of CSD-related neurological disorders. Toll-like receptors (TLR) are master regulators of innate immune function and involved in the activation of inflammatory responses in the brain. TLR3 agonist poly I:C exerts anti-inflammatory effect and prevents cell injury in the brain. The aim of the present study was to examine the effect of systemic administration of poly I:C on the release of cytokines (TNF-α, IFN-γ, IL-4, TGF-β1, and GM-CSF) in the brain and spleen, splenic lymphocyte proliferation, expression of GAD65, GABAAα, GABAAβ as well as Hsp70, and production of dark neurons after induction of repetitive CSD in juvenile rats. Poly I:C significantly attenuated CSD-induced production of TNF-α and IFN-γ in the brain as well as TNF-α and IL-4 in the spleen. Poly I:C did not affect enhancement of splenic lymphocyte proliferation after CSD. Administration of poly I:C increased expression of GABAAα, GABAAβ as well as Hsp70 and decreased expression of GAD65 in the entorhinal cortex compared to CSD-treated tissues. In addition, poly I:C significantly prevented production of CSD-induced dark neurons. The data indicate neuroprotective and anti-inflammatory effects of TLR3 activation on CSD-induced neuroinflammation. Targeting TLR3 may provide a novel strategy for developing new treatments for CSD-related neurological disorders.

Are anti-brain antibodies in multiple sclerosis directed to myelin basic protein? Studies employing the Shiverer mouse mutant

The dysmyelinating mouse mutant Shiverer has a severe and relatively selective deficiency of myelin basic protein (MBP) in the central and peripheral nervous system. Nevertheless, Shiverer brain and control-mouse brain showed similar antigenic titers when tested by a complement fixation assay against a panel of 14 multiple sclerosis (MS) sera and 6 MS CSF samples known to represent several specificities of antibrain antibodies. By analogy with experimental allergic encephalomyelitis, a sensitization to MBP has been proposed in MS. Our results, however, show that antibodies to other CNS antigens are quantitatively more important in this disease.

Myelin basic protein and demyelinating diseases

Myelin basic protein (MBP) is a major protein component of myelin sheath. Primarily because of its ability to induce experimental allergic encephalomyelitis (EAE) in animals, this protein has been considered to play an important role in the pathogenesis of multiple sclerosis (MS), which is one of the most common demyelinating diseases. Its precise measurement in the cerebrospinal fluid (CSF) has been uncommonly difficult, mainly due to immunoheterogeneity of MBP or MBP-like material. More recently, highly sensitive radioimmunoassay techniques utilizing well-characterized antisera have been developed that facilitated its use in the management of MS. The clinical course of MS is highly variable, and the disease is characterized by periods of remission and relapses. Many studies have demonstrated the release of MBP during relapses and elevated levels of MBP in the CSF can be detected if lumbar puncture is performed within 7 days of the onset of neurologic symptoms suggestive of MS. However, the presence of MBP is not an absolute indicator of MS, as elevated MBP levels are also frequently observed in other demyelinating diseases.

Immune responses to myelin antigens in multiple sclerosis

Multiple sclerosis is considered to be a putative immunopathologic disease and there has been considerable effort over the years to prove an autoimmune etiology for it. To date, the evidence is all indirect and there is no proof of either antibody and/or cell-mediated hypersensitivity to any single identifiable CNS constituent whether a constituent of normal CNS or specific to the CNS of MS patients.

Lymphocyte transformation in the presence of myelin basic protein in multiple sclerosis and control subjects

The transformation of lymphocytes in vitro in the presence of human myelin basic protein has been investigated in normal people, patients with multiple sclerosis (MS) and controls with other neurological diseases. There was little or no response at low concentrations (1--10 microgram/ml) but significant transformation at higher concentrations (100--1000 microgram/ml) in all three groups. There was no significant difference among the groups as a whole, but those MS patients who had had disease for more than 10 years did show greater responses than normal subjects (P less than 0.05). Increased responses could not be correlated with any other aspect of disease activity: in particular they were not increased in patients with acute relapses. The use of autologous serum instead of homologous AB Rhesus positive serum did not significantly alter lymphocyte responsiveness. The absence of any response in the presence of purified calf thymus histone suggests that the response to myelin basic protein indicates a low level of lymphocyte sensitization to this antigen even in normal subjects. The present evidence does not support a primary pathogenetic role for such a reaction in MS. The increased response in patients with a long duration of disease might merely be an effect of white matter damage or might represent an amplification of the normal immune response contributing to myelin breakdown and leading to the emergence of the progressive stage of the disease. The study of lymphocyte responsiveness over a wide range of concentrations of myelin basic protein is considered to resolve some of the controversy surrounding this subject in the literature.

Delayed hypersensitivity to human encephalitogenic protein as assayed by agarose leucocyte migration in multiple sclerosis patients

Using a leucocyte migration test (Clausen's direct agarose gel migration method) hypersensitivity to human encephalitogenic protein has been examined in 50 multiple sclerosis patients (group 1), 50 healthy persons (group 2) and 25 patients with other neurological diseases (group 3). In group 1, 30 MS patients (60%) show an abnormal migration index, manifested either as inhibition or stimulation of migration; 29 controls in group 2 (58%), 11 O.N.D. patients in group 3 (44%) show an abnormal migration index. These results mean that lymphocyte hypersensitivity to myelin basic protein appears neither to be constant nor specific to multiple sclerosis. Three migration index curve types at different antigen concentration are obtained: monophasic curves within the normal index zones; monophasic curves staying in the inhibition or stimulation zone and biphasic curves with dose-effect relationship. Whatever the antigen used, this dose-effect relationship implies that the test must be carried out at different concentrations. The meaning of spontaneous sensitisation in healthy controls is discussed.

Aspects of cellular immunity in multiple sclerosis. Antigen-reactivity of lymphocytes and lymphokine activity

Some new results of cell-mediated immunity in multiple slcerosis (MS) are presented, based on the determination of charge-changing lymphokines as products of antigen sensitive lymphocytes (C PAL), obtained by several forms of the electrophoretic mobility (EM) method. Lymphocytes from MS react to myelin basic protein (BP), the reactivity in other neurological diseases depending on the degree of destruction of nervous parenchyma. Applying a membrane-associated antigen from normal brain (NTA), positive reactivity of MS lymphocytes was obtained. Besides the usual determination of lymphokines in vitro the sensitive EM test allows the demonstration of lymphokine activities in vivo; i.e. in body fluids such as cerebrospinal fluid (CSF) and serum. In CSF of MS a high lymphokine activity was found. The differentiation of lymphokines and comparison between in vitro and in vivo activity were carried out. Moreover, a characteristic lymphokine pattern for MS with high activities in all regions of molecular weight, especially in the CSF, could be detected. On the basis of these findings, important also from the pathogenetic point of view, a diagnostic scheme for MS is suggested, consisting of a program of determination of the immuno-reactive CSF syndrome and some special procedures, including examination of lymphocyte reactivity.

E rosette-forming lymphocytes in multiple sclerosis patients. Basic protein stimulation of rosette-forming cells

"Total" and "active" T cells were enumerated using sheep red blood cell (SRBC) rosetting technique. The percentages of "total" and "active" T lymphocytes were not significantly different in multiple sclerosis patients as compared to other neurological disorders and/or healthy controls. However, the number of "avid" T cells binding more than three SRBC was significantly increased in MS patients. Active E rosette test has shown hypersensitization to myelin basic protein in 50% MS patients and 31% OND patients. All healthy controls studied, except one had negative response.

In vitro cell-mediated immunity of cerebrospinal-fluid lymphocytes to myelin basic protein in primary demyelinating diseases

In an attempt to characterize the immunologic reactivity of cerebrospinal-fluid lymphocytes in demyelinating diseases, we compared the myelin-basic-protein-induced in vitro responses of these cells to peripheral blood lymphocytes from the same subjects with a variety of neurologic diseases. Peripheral blood lymphocytes from patients with acute disseminated encephalomyelitis and progressive multiple sclerosis had increased reactivity as compared to those of normal volunteers (P less than 0.01 and P less than 0.05, respectively). Cerebrospinal-fluid lymphocytes from patients with acute disseminated encephalomyelitis and acute and progressive (but not stable) multiple sclerosis were more reactive than cells from subjects with other neurologic diseases (P less than 0.005, P less than 0.02 and P less than 0.05, respectively). Cerebrospinal-fluid lymphocytes manifested a greater reactivity than peripheral blood lymphocytes in acute and progressive multiple sclerosis but not in acute disseminated encephalomyelitis. These findings demonstrate that lymphocytic cells reactive to myelin basic protein are present in the spinal fluid during active demyelinating disease; and that these cells may be more reactive than peripheral blood lymphocytes.