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

Endoneurial injection of antisera to myelin antigens

When antisera to purified myelin antigens were injected into rat sciatic nerves, some produced significant demyelination, whereas others merely induced an inflammatory infiltrate. Extensive demyelination was produced by antisera to galactocerebroside and the peripheral nerve glycoprotein P0. Demyelination resulting from injections of antisera to ganglioside GM1, P2, myelin basic protein, sulfatide, and glucocerebroside did not exceed that produced by normal rabbit serum. Addition of guinea pig complement had no effect. It is of interest that the greatest demyelination followed injection of antisera to two molecules, galactocerebroside and P0, the main antigenic determinants of which present at the Schwann cell surface.

Immunopathologic features of retinal lesions in multiple sclerosis

To further characterize the nature of retinal periphlebitis and retinitis in multiple sclerosis, immunoperoxidase studies were performed on retinal tissue from multiple sclerosis patients at autopsy. Antibodies against myelin basic protein stained the optic nerve but not the retina. Both normal and multiple sclerosis retinas showed staining of Müller cells with Leu-7 (a monoclonal antibody that cross-reacts with myelin associated glycoprotein and natural killer cells). Nerve fiber bundles of the optic nerve in cases with multiple sclerosis and controls also showed staining with Leu-7 antibody. Tissue-bound IgG was demonstrated on retinal ganglion cells in six of seven multiple sclerosis cases but not in controls.

Derivation of ganglioside-specific T cell lines of suppressor or helper phenotype from cerebrospinal fluid of multiple sclerosis patients

In order to investigate the specificity of activated T cells in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS), we have cultured cells in the presence of mitogen-free IL-2 but without any antigen. Two T cell lines have been derived and showed specific reactivity to certain purified gangliosides (GM1, GD1a, GD1b and GQ1b). However, responses to other brain and viral antigens were not seen, and neither were T cell lines from peripheral blood lymphocytes (PBL) of normal, MS or other neurological disease patients stimulated by these gangliosides. Release of IL-2 could be detected after incubation of these CSF lines with specific gangliosides. One line exhibited predominantly helper/inducer (T4+) phenotype whilst the other was suppressor/cytotoxic (T8+), and further analysis indicated it could be of the suppressor phenotype. These data may have implications for T cell-induced demyelination in MS.

Chronic relapsing experimental autoimmune encephalomyelitis. Transient presence in blood of lymphocytes sensitised to encephalitogen at onset of inflammatory relapses

Juvenile guinea pigs were immunised with homologous spinal cord and monitored daily over a 6-month period for neurological signs of chronic relapsing experimental autoimmune encephalomyelitis (CREAE). At various times animals were killed, numbers of leucocytes in their cerebrospinal fluid (CSF) quantified, and in vitro proliferative responses of blood lymphocytes to myelin basic protein (MBP) and its encephalitogenic nonapeptide (NP) determined. After recovering from initial acute clinical signs, animals suffered at least two major spontaneous relapses separated by remission periods of 4-5 weeks mean duration. In the early chronic phase, 5-12 weeks post-immunisation (pi), 63% of the animals recovered fully from relapses, whereas relatively irreversible neurological deficits predominated in the late chronic phase. During the acute and chronic phases, there was a highly significant correlation between clinical severity and CSF pleocytosis only in animals killed within 24 h of onset of a clinical exacerbation associated with more than 100 leucocytes/microliter of CSF. Guinea pigs with this degree of CSF pleocytosis were defined as suffering an inflammatory relapse. Blood lymphocytes responsive to MBP and NP were detected only in animals killed at the onset of clinical signs of either the acute or an inflammatory relapse. This dynamic relationship suggests that migration of encephalitogen-responsive lymphocytes via the blood to the central nervous system could produce certain relapses in CREAE. However, the relative paucity of CSF leucocytes in most animals killed during relapses between 15-26 weeks pi suggests that other factors may elicit neurological exacerbations in the late chronic phase.

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.

Isolation of myelin basic protein-reactive T-cell lines from normal human blood

T-Cell lines which responded by proliferation to the autoantigen, myelin basic protein (MBP), were isolated from the blood of six of nine normal humans. These T-cell lines could be maintained in in vitro culture for up to 2 months through the use of Interleukin 2 and repeated MBP stimulation. Optimal antigen-induced proliferation required both antigen and antigen-presenting cells found in the adherent cell population of autologous peripheral blood mononuclear cells (PBM). The T-cell lines were predominantly of the helper phenotype (OKT3+, OKT4+, OKT8-) and responded to both human and guinea pig myelin basic protein.

Cellular hypersensitivity to gangliosides and myelin basic protein in multiple sclerosis

Peripheral blood lymphocytes from patients with multiple sclerosis (MS), other neurological diseases and healthy controls were investigated for the presence of cell-mediated hypersensitivity to brain gangliosides and myelin basic protein using an active E-rosette assay. Sensitivity to myelin basic protein and gangliosides was found in MS patients in acute relapse and with progressive disease, whereas no sensitivity was found in MS patients in remission. Patients with other neurological diseases showed no response to gangliosides, but sensitization to myelin basic protein was found in a patient with leucoencephalopathy and in 4 of 6 stroke patients. Healthy controls did not respond to either antigen. In MS patients a positive correlation was seen between lymphocyte responses to myelin basic protein and to gangliosides. The data suggest that in comparison to gangliosides, myelin basic protein is a weaker stimulator of active rosette-forming cells. Moreover, cellular hypersensitivity to myelin basic protein is not MS-specific and may be present as a consequence of brain damage. However, cellular hypersensitivity to gangliosides appears to be more specific to MS and may be important in the pathogenesis of the disease.

Immunological reactions against Mycoplasma pneumoniae in multiple sclerosis: preliminary findings

Humoral and cellular immune reactions against Mycoplasma pneumoniae (MPn) were investigated in 18 multiple sclerosis (MS) patients. All patients were in the remission stage. Complement-fixing antibodies against MPn were present in serum and cerebrospinal fluid, concentrated to contain the same protein levels. The CSF titres after concentration were as high as or higher than the corresponding serum titres, thus indicating intrathecal antibody production. Sensitization to MPn was demonstrable in all 18 MS patients by the antigen-reactive active E-rosette assay and antibody-dependent cellular cytotoxicity assay, in 17 of the 18 patients by the lymphocyte transformation test and in 8 patients by the cell-mediated cytotoxicity assay. The possibility of a pathogenetic role of MPn for MS is discussed.

Sensitization of cerebrospinal fluid and peripheral blood lymphocytes to myelin basic protein in multiple sclerosis

Cerebrospinal fluid (CSF) and peripheral blood (PB) lymphocyte sensitization to rabbit myelin basic protein (MBP) in 44 multiple sclerosis (MS) patients, 21 patients with other neurological diseases (OND) and 14 persons with neurosis was studied with the antigen-active rosette forming cells (Ag-ARFC) assay. The frequency of sensitization of CSF lymphocytes to MBP in groups of MS patients in the relapse stage and the chronic progressive stage was higher than in the group of MS patients in the stable stage and the OND patients. None of the healthy subjects showed a positive reaction with MBP. In BP there were no differences in the incidence of sensitization to MBP between patients in various stages of the disease, but it was higher than in the group of patients with OND and neuroses. In the patients who had suffered from MS for less than 4 years, sensitization to MBP was more common in CSF lymphocytes than in BP lymphocytes. The results suggest that primary sensitization to MBP occurs in CSF, and is probably secondary to myelin damage. However at present it is difficult to determine the extent to which sensitization of CSF and PB lymphocytes to MBP play a role in further demyelination processes.

Cell-mediated immunity in multiple sclerosis as determined by sensitivity of different lymphocyte populations to various brain tissue antigens

Peripheral blood lymphocytes from patients with multiple sclerosis (MS) or other neurological diseases and from healthy individuals were separated by density gradient sedimentation into several subfractions. Individual cell populations were cultured in the presence of several human brain tissue antigens. In comparison to controls, mononuclear cells with a density of less than 1.077 gm/cm3 from MS patients displayed a significantly increased sensitivity after incubation with purified human myelin basic protein (MBP) but not with other brain tissue antigens. In particular, the lymphocytes of patients suffering from MS for more than four years reacted positively with MBP, suggesting that the reaction dependent. No difference between MS patients and controls in sensitivity to any brain tissue antigen could be detected with cells of lower density (i.e., 1.073 to 1.069 gm/cm3 or less than 1.069 gm/cm3). Comparable lymphocyte activity was found to antigens isolated from both MS and control brain tissue. These results suggest that patients with chromic progressive MS have a secondary immune activity to MBP.

Multiple sclerosis-lymphocyte transformation with multiple sclerosis and normal brain myelin basic protein and subcellular fractions

Possible sensitisation of peripheral blood mononuclear cells from multiple sclerosis (MS) patients was studied in the presence of both normal and MS brain subcellular fractions. Myelin, synaptosomal and microsomal fractions and myelin basic protein were prepared by sucrose density gradient centrifugation from normal and MS brain. These preparations were added to mononuclear cell microcultures from the peripheral blood of nine acute and six chronic MS patients, 10 patients with other neurological diseases and 10 normal subjects. There was no significant increment in the peripheral blood mononuclear cell transformation of any of the acute MS patients with any of the fractions. Therefore there is no evidence that immunity to antigens in any of the fractions of MS or normal brain is of primary pathogenetic importance. A small increment in peripheral blood mononuclear cell transformation in the presence of several fractions was observed in two of six chronic MS patients, which might indicate the development of a secondary immune response after prolonged disease.

Immune responses in experimental allergic neuritis

The antibody and cell mediated immune responses were investigated in inbred Lewis rats with experimental allergic neuritis (EAN) induced by either P2, a protein purified from the bovine cauda equina nerve roots, or whole bovine nerve root myelin. In the P2 immunised animals both antibodies to P2 detected by radioimmunoassay and cell-mediated immunity to P2 assayed by skin testing appeared before the onset of EAN and persisted during and after the disease. In the myelin immunised animals the antibody titres were lower and somewhat delayed and the skin tests became negative at the height of the disease. Complement-fixing antibodies to galactocerebroside, which have been implicated in the production of demyelination under some circumstances, could not be detected in the serum after immunisation with either P2 or myelin. EAN was transferred passively with lymph node cells from rats immunised with either P2 or myelin although anti-P2 antibodies could not be detected in the serum of recipients with EAN. The results favour a cell-mediated immune response to P2 as the most important pathogenetic mechanism in EAN induced wtih whole myelin in the rat.

The significance of abnormal immune responses in patients with multiple sclerosis

Early diagnosis of multiple sclerosis (MS) may be assisted by tests for the abnormal immune responses of the central nervous system (CNS) including oligoclonal IgG bands in the cerebrospinal fluid (CSF), increased CNS IgG synthesis, increased CNS antibody synthesis against multiple viruses and increased numbers of enlarged lymphoid cells in the CSF. Alterations in immunological responses are important in the pathogenesis of MS. Further studies are needed, however, to identify the antigen(s) and/or antibodies responsible for oligoclonal IgG in the CSF of MS patients. Also, the cause(s) for the other immunological abnormalities with diagnostic importance need to be identified. The increased synthesis of antibodies against multiple unrelated viruses suggests generalized alteration in the immune regulatory system. The etiology of MS might be multifactorial involving abnormal immunological responses, possibly precipitated by infectious agents acquired during childhood by genetically susceptible individuals. The immunological responses including alterations in myelin basic protein concentration, antimyelin antibody and immune complex activities in CSF, and in vitro stimulation, suppression and migration inhibition of blood lymphocytes appear to correlate with stage of MS and severity of CNS damage. Some of the tests may become useful in estimating the prognosis of the disease. Longitudinal studies are needed to clarify the sensitivity of the diagnostic and prognostic immunological tests and etiological significance of these abnormalities in MS.