Ability Of Myelin Basic Protein Research Articles

Myelin basic protein-reactive T cells induce conduction failure in vivo but not in vitro.

The ability of myelin basic protein (MBP)-reactive T cells to induce conduction failure was investigated and. With the model, somatosensory evoked potentials (SEP) were recorded before and during adoptively transferred experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Maximum amplitude SEP were reached within 15 min of anesthesia. During EAE, the SEP decreased considerably and their onset was delayed. However, the compound action potentials (CAPs) recorded from Lewis rat optic nerves incubated with encephalitogenic T cells were not affected, emphasizing the importance of environmental factors. This study shows that the model described here is an useful means of investigating the neurological disorders associated with EAE.

Cultured human monocytes release proinflammatory cytokines in response to myelin basic protein

In human cultured monocytes we examined the ability of myelin basic protein (MBP) to induce the production of proinflammatory cytokines potentially involved in inflammatory demyelination. Northern blots and specific immunoassays demonstrated that monocytes incubated with optimal doses of MBP showed increased mRNA expression and release of tumor necrosis factor (TNF- α), interleukin-1 β (IL-1 β), interleukin-6 (IL-6), interleukin-8 (IL-8) but not of interleukin-12/p40 (IL-12/p40). We also showed that cytokine production by MBP-stimulated monocytes was abrogated by incubation with Dexamethasone. These data suggest that interaction of mononuclear phagocytes with MBP may participate in the regulatory process of cytokine production during inflammatory demyelination and support the beneficial role of corticosteroids therapy in aberrant immune responses to the myelin sheath.

Bilayer-stabilizing properties of myelin basic protein in dioleoylphosphatidylethanolamine systems

31P-NMR and X-ray diffraction techniques are used to study the comparative ability of myelin basic protein (MBP) vs. other basic proteins to convert hexagonal (H II) phases to stable lamellar (L α) structures. Pure dioleoylphosphatidylethanolamine (DOPE) at pH 9 and 7, and mixtures of DOPE/phosphatidylserine (PS) (95:5 and 80:20% w/w) at pH 7 were employed for this investigation. The polymorphic behavior of the lipid suspensions was evaluated in the presence and absence of several basic proteins (MBP, calf thymus histone, lysozyme, melittin) and the cationic polypeptide, polylysine (PL). Each of the proteins and PL was capable of binding the pure DOPE H II phase at pH 9 but with varying morphological consequences, i.e., lamellar stabilization (MBP, histone, PL), formation of new protein-DOPE H II phases (lysozyme) or lipid disordering/vesiculation (melittin). Reduction to pH 7 resulted in the dissociation of protein from DOPE — with the exception of melittin — and the reformation of a pure lipid H II phase. Additions of PS to DOPE at pH 7 facilitated protein binding, but among the proteins examined, only MBP was capable of converting the lipid suspension into a stable multilamellar form. Differences in the lipid morphology produced by each protein are discussed in terms of protein physicochemical characteristics. In addition, a possible relationship between MBP-lipid interactions and the stability of myelin sheath lipid multilayers is inferred from the significant bilayer-stabilizing capacity of MBP.

IgG Subclass Responses and Immediate Skin Sensitivity in Guinea-Pigs with Chronic Relapsing Experimental Allergic Encephalomyelitis

In strain-13 guinea-pigs inoculated for chronic relapsing experimental allergic encephalomyelitis (CR-EAE), IgG1 and IgG2 subclass antibody responses were investigated using single radial immunodiffusion and enzyme-linked immunosorbent assays (ELISA) for IgG1 and IgG2 specific for whole cord, myelin, myelin basic protein and Mycobacterium tuberculosis. The early acute stage revealed no increase in IgG1 but was associated with increased levels of IgG2 specific for neural and adjuvant components. Throughout the chronic phase of the disease, there were increased levels of IgG of both subclasses specific for the antigens tested but a preferential synthesis of IgG1. Levels of both IgG1 and IgG2 specific for neuroantigens were lowest in those guinea-pigs which did not develop signs of chronic disease. Immediate skin sensitivity against a wide range of neural antigens was not demonstrated though positive results may have been masked by the ability of myelin basic protein to induce non-specific mast cell degranulation and by altered histamine responsiveness in disease. Guinea-pigs with chronic paralysis had a lower skin sensitivity to histamine, compound 48/80 and M. tuberculosis than those in remission.

The induction of liposome aggregation by myelin basic protein

Myelin basic protein derived from bovine spinal cord has been interacted with liposomes of varying brain lipid compositions. The effects of salt and protein concentration on liposome cross linking has been investigated. It appears that myelin basic protein cannot link liposomes composed of brain-derived phosphatidyl choline. Myelin basic protein can link liposomes composed of phosphatidyl serine; phosphatidyl serine + cholesterol; phosphatidyl serine + cholesterol + cerebroside sulphate. Linking of liposomes occurs at protein concentrations lower than those required for myelin basic protein dimers to be formed. Therefore, it seems that the monomeric form of myelin basic protein links lipid bilayers. The presence of cholesterol in the bilayer increases the ability of myelin basic protein to aggregate such liposomes compared with the linking ability of the polycationic polypeptide, poly-l-lysine.