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PubMed2003

Antibodies to myelin basic protein, myelin oligodendrocytes peptides, alpha-beta-crystallin, lymphocyte activation and cytokine production in patients with multiple sclerosis.

OBJECTIVE: To measure neurone-specific humoral and cellular immune parameters in MRI-positive patients with multiple sclerosis (MS). BACKGROUND: It has been postulated from animal models for MS and in situ evidence in MS patients that antibodies, activated T cells and proinflammatory cytokines are involved in the destruction of myelin sheaths and loss of oligodendrocytes in active areas. SUBJECTS AND METHODS: Blood samples were obtained from 20 healthy control subjects and 20 patients with abnormal MRI and clinical diagnosis of MS. Sera were tested for levels of IgG, IgM and IgA against myelin basic protein (MBP), myelin oligodendrocyte glycoprotein (MOG) peptides, and a small heat-shock protein, alpha-beta-crystallin. Lymphocytes were isolated and cultured in the presence or absence of MBP, MOG peptides and alpha-beta-crystallin, measured for stimulated T cells, cytokine production and compared with controls. RESULTS: Patients with MS showed the highest levels of IgG, IgM or IgA antibodies against one or all three tested antigens. Moreover, in the presence of MBP, MOG peptides or alpha-beta-crystallin, a significant percent- age of lymphocytes from MS patients underwent blast transformation, which resulted in high levels of interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha) and tumour necrosis factor beta (TNF-beta) production. Sensitivity of these assays was 60-80% and specificity, 65-70%. CONCLUSIONS: Detection of antibodies against MBP, MOG peptides, alpha-beta-crystallin, lymphocyte stimulation and production of proinflammatory cytokines in response to these antigens could be used as surrogate markers for the confirmation of MS diagnosis. A combination of antibodies, lymphocyte activation or cytokine production with abnormal MRI may significantly increase the sensitivity and specificity of MS diagnosis.

Adult↗
PubMedDate not supplied

Neuron-specific enolase, S-100 protein, myelin basic protein and lactate in CSF in dementia.

The pattern of injury of the specific cell structures of the central nervous system (CNS) is different in the various types of the dementia syndrome. We challenged the hypothesis that this could be reflected in specific patterns of brain-specific proteins in the cerebrospinal fluid (CSF). The neuron-specific enolase (NSE), S-100, myelin basic protein (MBP) and lactate levels were retrospectively analyzed in the CSF of 159 patients with various types of dementia. A previous study from our department demonstrated age-related reference values for the brain-specific proteins in the CSF. The present study affirmed the strikingly high NSE and S-100 values in the CSF of patients with autopsydiagnosed Creutzfeld-Jacob disease: NSE, S-100 and MBP levels in the CSF of patients with various other types of dementia, and controls, did not differ significantly. Therefore we concluded that a single determination of CSF concentrations of these brain-specific proteins were of little value in the differential diagnosis of the dementia syndrome. In the diagnosis of normal pressure hydrocephalus increased levels of CSF lactate may be helpful.

Aged↗
PubMed1976

Potentiation of C56-initiated lysis by leucocyte cationic proteins, myelin basic proteins and lysine-rich histones.

Synthetic polycations such as poly-L-lysine (PLL) have recently been shown to enhance C56-initiated lysis by neutralization of serum-derived inhibitors of the C567 complex, collectively designated C567-INH. In the present report we have examined the effect of several naturally occurring polycations on C56-initiated lysis. Lysosomal granule extracts from rabbit peritoneal exudate cells were found to potentiate C56-initiated lysis via counteraction of C567-INH in the fluid phase; this was dependent upon the amount of C567-INH present and independent of cell concentration. The basic proteins of guinea-pig, bovine, and monkey myelin as well as lysine-rich histones also potentiated EC567 formation, but this effect seemed to occur predominantly at the cell surface. The presence of biologically derived cationic proteins at sites of complement activation during inflammation thus might lead to enhanced tissue damage by favouring the formation of cell-C567 intermediates by either or both of these mechanisms.

Animals↗
PubMed1990

A hydroxyproline-containing protein from shark brain that is related to myelin basic protein.

Myelin basic protein (MBP) from shark (Chondricthyes) consists of a simpler mixture of charge isomers than human MBP. About two-thirds of the total amount applied to a CM-52 cellulose cation-exchange column was recovered in the unbound fraction of the column; the remaining one-third bound to column and was eluted as a single OD280 peak. This bound material did not sow the usual pattern of charge microheterogeneity found with human or bovine MBP. The unbound fraction was composed of a high molecular weight protein (55-60 kDa), which constituted most of this protein fraction and a low molecular weight protein (approximately 18 kDa). The amino acid composition of our unbound fraction was similar to that reported earlier. The Glx (glutamic acid + glutamine) was increased about threefold whereas the Arg content was only about 25% of that of the 18.5 kDa variant of bovine or human origin. The presence of hydroxyproline (1.2 residues/100) in this protein was noteworthy, identification of which was achieved by amino acid analysis in two different systems and by mass spectrometry. In the precolumn derivatization method, hydroxyproline eluted at 2.7 min; in the postcolumn derivatization method it eluted at 12.2 min. Identification of hydroxyproline was completed by fast atom bombardment-mass spectral analysis. The effect of hydroxyproline on the secondary structure of this protein is being studied. Verification that this high molecular weight protein contained MBP sequences within its primary structure was confirmed by immunological methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1985

Electron microscopic immunocytochemical localization of myelin proteolipid protein and myelin basic protein to oligodendrocytes in rat brain during myelination.

Electron microscopic immunocytochemical studies were carried out to localize myelin basic protein and myelin proteolipid protein during the active period of myelination in the developing rat brain using antisera to purified rat brain myelin proteolipid protein and large basic protein. The anti-large basic protein serum was shown by the immunoblot technique to cross-react with all five forms of basic protein present in the myelin of 8-day-old rat brain. Basic protein was localized diffusely in oligodendrocytes and their processes at very early stages in myelination. The immunostaining for basic protein was not specifically associated with any subcellular structures or organelles. The ultrastructural localization of basic protein suggests that it may be involved in fusion of the cytoplasmic faces of the oligodendrocyte processes during compaction of myelin. Immunoreactivity in the oligodendrocyte and myelin due to proteolipid protein appeared at a later stage of myelination than did that due to basic protein. Staining for proteolipid protein in the oligodendrocyte was restricted to the membranes of the rough endoplasmic reticulum, the Golgi apparatus, and apparent Golgi vesicles. The early, uncompacted periaxonal wrappings of oligodendrocyte processes were well stained with antiserum to large basic protein whereas staining for proteolipid protein was visible only after the compaction of myelin sheaths had begun. Our evidence indicates that basic protein and proteolipid protein are processed differently by the oligodendrocytes with regard to their subcellular localization and their time of appearance in the developing myelin sheath.

Animals↗
PubMed1996

Treatment of experimental encephalomyelitis with a novel chimeric fusion protein of myelin basic protein and proteolipid protein.

It has been shown that peripheral T cell tolerance can be induced by systemic antigen administration. We have been interested in using this phenomenon to develop antigen-specific immunotherapies for T cell-mediated autoimmune diseases. In patients with the demyelinating disease multiple sclerosis (MS), multiple potentially autoantigenic epitopes have been identified on the two major proteins of the myelin sheath, myelin basic protein (MBP) and proteolipid protein (PLP). To generate a tolerogenic protein for the therapy of patients with MS, we have produced a protein fusion between the 21.5-kD isoform of MBP (MBP21.5) and a genetically engineered form of PLP (deltaPLP4). In this report, we describe the effects of treatment with this agent (MP4) on clinical disease in a murine model of demyelinating disease, experimental autoimmune encephalomyelitis (EAE). Treatment of SJL/J mice with MP4 after induction of EAE either by active immunization or by adoptive transfer of activated T cells completely prevented subsequent clinical paralysis. Importantly, the administration of MP4 completely suppressed the development of EAE initiated by the cotransfer of both MBP- and PLP-activated T cells. Prevention of clinical disease after the intravenous injection of MP4 was paralleled by the formation of long-lived functional peptide-MHC complexes in vivo, as well as by a significant reduction in both MBP- and PLP-specific T cell proliferative responses. Mice treated with MP4 were resistant to disease when rechallenged with an encephalitogenic PLP peptide emulsified in CFA, indicating that MP4 administration had a prolonged effect in vivo. Administration of MP4 was also found to markedly ameliorate the course of established clinical disease. Finally, MP4 therapy was equally efficacious in mice defective in Fas expression. These results support the conclusion that MP4 protein is highly effective in suppressing disease caused by multiple neuroantigen epitopes in experimentally induced demyelinating disease.

Adoptive Transfer↗
PubMed1986

Cloned proteolipid protein and myelin basic protein cDNA. Transcription of the two genes during myelination.

cDNA clones of rat brain proteolipid protein (PLP), also named lipophilin, the major integral myelin membrane protein, and of myelin basic protein (MBP), the major extrinsic myelin protein, have been isolated from a rat brain cDNA library cloned into the PstI site of pBR322. Poly(A)+ RNA from actively myelinating 18-day-old rats has been reversely transcribed. Oligonucleotides synthesized according to the established amino-acid sequence of lipophilin and the nucleotide sequence of the small myelin basic protein of the N-terminal, the central and C-terminal region of their sequences were used as hybridization probes for screening. The largest insert in one of several lipophilin clones was 2,585 base pairs (bp) in length (pLp 1). It contained 521 bp of the C-terminal coding sequence and the complete 2,064 bp long non-coding 3' sequence. The myelin basic protein cDNA insert of clones pMBP5 and pMBP6 is 2,530 bp long and that of clones pMBP2 and pMBP3 640 bp. These clones were also characterized. pMBP2 was sequenced and used together with the lipophilin cDNA clones as hybridization probes to estimate the lipophilin and myelin basic protein mRNA levels of rat brain during the myelination period. The expression of the lipophilin and myelin basic protein genes during development of the myelin sheath appears to be strictly coordinated.

Animals↗
PubMed1991

Enzymic methylation of myelin basic protein in myelin.

Myelin fractions with different degrees of compaction were isolated from bovine brain, and post-translational methylation of membrane-associated proteins was studied. When the purified myelin-basic-protein-specific protein methylase I and S-adenosyl-L-[methyl-14C]methionine were added exogenously, the most compact myelin fraction exhibited higher methyl-accepting activity than the less compact dense fractions. The methylated protein was identified as myelin basic protein (18.4 kDa) exclusively among the several myelin proteins from all membrane fractions, by SDS/PAGE/radioautography of methyl-14C-labelled membrane proteins. The methyl-14C-labelled amino acid residue in the basic protein was identified by h.p.l.c. as NG-methylarginine, indicating the high degree of specificity for the arginine residue as well as the myelin basic protein in the intact myelin membranes. The possibility of a charge alteration of myelin basic protein resulting from its arginine methylation was investigated by using the purified component 1 of myelin basic protein. The methylated component was shown to be less cationic than the unmethylated component by Bio-Rex 70 cation-exchange chromatography, since the former preceded the latter. However, in the presence of the denaturant (guanidinium chloride), the two species were co-eluted, indicating that the charge difference between methylated and unmethylated myelin basic protein can only be shown under the renatured condition.

Amino Acids↗
PubMed2006

Myelin basic protein: a multifunctional protein.

Myelin basic protein (MBP), the second most abundant protein in central nervous system myelin, is responsible for adhesion of the cytosolic surfaces of multilayered compact myelin. A member of the 'intrinsically disordered' or conformationally adaptable protein family, it also appears to have several other functions. It can interact with a number of polyanionic proteins including actin, tubulin, Ca(2+)-calmodulin, and clathrin, and negatively charged lipids, and acquires structure on binding to them. It may act as a membrane actin-binding protein, which might allow it to participate in transmission of extracellular signals to the cytoskeleton in oligodendrocytes and tight junctions in myelin. Some size isoforms of MBP are transported into the nucleus and thus they may also bind polynucleotides. Extracellular signals received by myelin or cultured oligodendrocytes cause changes in phosphorylation of MBP, suggesting that MBP is also involved in signaling. Further study of this very abundant protein will reveal how it is utilized by the oligodendrocyte and myelin for different purposes.

Amino Acid Sequence↗
PubMed1987

A correlation between cerebrospinal fluid myelin basic protein and anti-myelin basic protein in multiple sclerosis patients.

Free and bound levels of myelin basic protein (MBP) and anti-myelin basic protein (anti-MBP) antibodies were measured by radioimmunoassay in the cerebrospinal fluid of patients with multiple sclerosis who were experiencing acute exacerbations or progressing disease. In a cross-sectional study, free levels of MBP correlated with those of free anti-MBP, and bound MBP levels correlated with those of bound anti-MBP in both groups of patients with active disease. However, acute exacerbations of multiple sclerosis were characterized by higher free MBP and anti-MBP levels with lower levels of bound fractions. Conversely, patients with progressing disease had higher titers of bound than free fractions. Longitudinal studies of individual patients confirmed the association of higher titers of free anti-MBP with acute exacerbations and higher levels of bound anti-MBP with chronic progressing disease.

Adult↗
PubMed1995

[Simplified enzyme-linked immunoadsorbent assays for myelin basic protein and antibodies to myelin basic protein].

Synchronous quantitative determination using simplified enzyme-linked immuno adsorbent assay has been developed for myelin basic protein (MBP) and antibodies to myelin basic protein (Anti-MBP). Antisera were prepared by immunizing rabbits with purified MBP from human white matter. Antibodies to MBP was conjugated with horseradish peroxidase (HRP) by using modified periodate oxidation method. Minimum detection amounts of MBP and Anti-MBP are 0.25 ng/ml and 0.20 ng/ml respectively. The activities of Anti-MBP-HRP conjugates are stable (stored at -30 degrees C) for at least 2 years. The detection procedure can be accomplished within 24 hours.

Animals↗
PubMed1995

[Enzyme-linked immunoadsorbent assays for myelin basic protein and antibodies to myelin basic protein in serum and CSF of patients with diseases of the nervous system].

Simplified enzyme-linked immunoadsorbent assays (ELISA) for myelin basic protein (MBP) and antibodies to myelin basic protein (Anti-MBP) have been used to test 337 patients with diseases of the nervous system including 36 compressive diseases (CMP), 33 multiple sclerosis (MS), 34 cerebrovascular diseases (CVD), 31 inflammatory diseases of central nervous system (ID), 161 epilepsy (EP) and 42 other nervous diseases (OND). Comparison of results among various groups indicates that serum mean MBP values of CMP, MS, CVD, ID and EP groups are significantly higher than those of OND group and normal control (P < 0.01). The serum mean MBP value of 33 acute trauma patients with spine fracture and paraplegia, the majority of CMP group, is the highest compared with MS group (P < 0.05), CVD, ID and EP groups (P < 0.01). CSF mean MBP value of 15 CVD patients is markedly greater than that of OND group (P < 0.05). No statistically significant differences are found in serum MBP values between OND group and normal control, and in serum and CSF Anti-MBP values among six groups by using our method.

Autoantibodies↗
PubMed1986

Effect of methylprednisolone on CSF IgG parameters, myelin basic protein and anti-myelin basic protein in multiple sclerosis exacerbations.

Clinical exacerbations of multiple sclerosis (MS) are characterized by elevated levels of cerebrospinal fluid (CSF) myelin basic protein (MBP). The purposes of this study were to determine whether anti-MBP antibodies are present in increased titer in CSF of MS patients with exacerbations, and whether they can be suppressed by the administration of immunosuppressive dosages of methylprednisolone (MP). A solid phase radio-immunoassay (RIA) was used to detect free and total anti-MBP antibodies before and after acid hydrolysis of CSF. In MS exacerbations, the majority of elevated anti-MBP is in the free form. With the exception of subacute sclerosing panencephalitis (SSPE) and some cases of post infectious encephalomyelitis, anti-MBP antibodies are not present in either MS patients in remission or in non-MS controls. Anti-MBP levels remained elevated over a 10 day period when patients are managed by bed rest only or when treated with intravenous (IV) ACTH. IV administration of MP in "high" (160 mg/day) or "mega" (2 g/day) dosages produces a highly significant reduction of both MBP (p less than 0.01) and anti-MBP (p less than 0.001) levels. Total intrathecal IgG synthesis is also significantly suppressed by IV-MP but not by ACTH.

Adrenocorticotropic Hormone↗
PubMed1983

Failure to detect antibodies to myelin basic protein or peptic fragments of myelin basic protein in CSF of patients with MS.

Using the sodium sulfate precipitation radioimmunoassay and solid-phase radioimmunoassay, we measured antibody to intact human myelin basic protein and myelin basic protein peptic fragments, residues 1-44, 45-89, and 90-170, in CSF. Comparable levels of binding were obtained for MS and normal CSF by both tests. The increased amount of CSF IgG in MS patients cannot be attributed to specific antibody against myelin basic protein or its peptic fragments.

Adult↗
PubMed1993

Hydrolysis of myelin basic protein in myelin membranes by granzymes of large granular lymphocytes.

Immune-mediated demyelination initially manifests as a separation of myelin lamellae followed by loss of myelin proteins and eventual loss of myelin membranes. Myelin basic protein, one of the major structural proteins of myelin, is highly vulnerable to various proteases derived from diverse cell types. Killer lymphocytes such as CTL, in addition to other immune effectors, have been implicated in inflammatory demyelination. In addition to a pore forming peptide, the granules of CTL and large granular lymphocytes (LGL) contain a number of serine esterases collectively called as granzymes. We studied the effect of these granule enzymes on myelin and found that LGL granule-extracts (LGL-g) hydrolyzed MBP in myelin membranes. LGL-g also cleaved purified MBP at neutral pH in a Ca2+ independent manner and this hydrolysis was inhibited by serine esterase inhibitors. In addition, absorption of LGL-g with antigranzyme A significantly reduced MBP hydrolysis. These findings implicated the granzymes in LGL-g, especially granzyme A, as the agent causing MBP degradation. Inasmuch as activation of CTL in the vicinity of myelinated axons can lead to granule exocytosis, hydrolysis of MBP by granzymes may be a significant event in myelin destruction.

Cell Membrane↗
PubMed1992

Is myelin basic protein crystallizable?

Myelin basic protein (MBP) is the predominant extrinsic protein in both central and peripheral nervous system myelins. It is thought to be involved in the stabilizing interactions between myelin membranes, and it may play an important role in demyelinating diseases such as multiple sclerosis. In spite of the fact that this abundant protein has been known for almost three decades, its three-dimensional crystal structure has not yet been determined. In this study we report on our extensive attempts to crystallize the major 18.5 kDa isoform of MBP. We used MBP having different degrees of purity, ranging from crude MBP (that was acid or salt extracted from isolated myelin), to highest purity single isoform. We used convention strategies in our search for a suitable composition of a crystallization medium. We applied both full and incomplete factorial searches for crystallization conditions. We analyzed the available data on proteins which have previously resisted crystallization, and applied this information to our own experiments. Nevertheless, despite our efforts which included 4600 different conditions, we were unable to induce crystallization of MBP. Previous work on MBP indicates that when it is removed from its native environment in the myelin membrane and put in crystallization media, the protein adopts a random coil conformation and persists as a population of structurally non-identical molecules. This thermodynamically preferred state presumably hinders crystallization, because the most fundamental factor of protein crystallization - homogeneity of tertiary structure--is lacking. We conclude that as long as its random coil flexibility is not suppressed, 18.5 kDa MBP and possibly also its isoforms will remain preeminent examples of proteins that cannot be crystallized.

Ammonium Sulfate↗