Bovine Myelin Basic Protein Research Articles

Experimental allergic optic neuritis (EAON) in the rabbit: A new model to study primary demyelinating diseases

In New Zealand albino rabbits the axons of the nerve fibre layer are myelinated over a long distance within the retina. Primary demyelination of these fibres was induced by sensitization of the animals to bovine cerebral white matter or myelin basic protein in complete Freund's adjuvant and challenge thereafter by intravitreous injection of basic protein (BP) or purified tuberculin (PPD). Production of segmental demyelination as a result of sensitization to brain-specific antigen (BP) and indifferent (PPD) antigen, shows that morphologically the same type of lesions can be induced by any antigen which will elicit cell-mediated immune reaction.

THE P2 PROTEIN OF BOVINE ROOT MYELIN: PARTIAL CHEMICAL CHARACTERIZATION1

Abstract—The P2 protein of bovine root myelin has chemical characteristics which differentiate it from other myelin basic proteins. The tryptic peptide map of the bovine P2 protein is distinctly different from the map of either the rabbit PI protein or the bovine CNS myelin basic protein. The tryptic peptides of the P2 protein show no overlap in either map positions or amino acid content with the peptides of the CNS myelin basic protein. Analysis of the individual peptides in the P2 map accounted for all of the amino acids present in the analysis of the whole protein. The P2 protein has a blocked NH2‐terminus, lysine at its COOH‐terminus and no hexosamine. CD studies revealed that the P2 protein has a very stable β‐structure in aqueous solution at neutral or basic pH and retains much of this structure in acid and in 8 M urea. It is suggested that these structural properties are relevant to the dual role of the P2 protein as a membrane constituent and as an antigen.

The P2 protein of bovine root myelin: isolation and some clinical and immunological properties.

Abstract— A small basic protein (mol.wt. 12,000), referred to as the P2 protein, was extracted with dilute acid from delipidated bovine root myelin and purified by ion exchange chromatography on cellulose phosphate. It appeared homogeneous on polyacrylamide gel electrophoresis. The P2 protein had a distinctly different amino acid composition than the larger basic protein (mol.wt. 18,000), referred to as the P1 protein, that is also present in peripheral nerve myelin. It contained relatively more hydrophobic residues and much less histidine and proline. The P2 protein conjugated with peroxidase was bound by lymph node cells and infiltrates in rabbits sensitized with whole bovine root myelin. No binding was evident with the bovine central nervous system myelin basic protein. Chemically and immunologically, the P2 protein appears to be specific to peripheral nervous system myelin. The isolated P2 protein produced mild clinical symptoms of experimental allergic neuritis, but no histological evidence of disease. It was suggested that the P2 protein is an important antigen for experimental allergic neuritis, and that its antigenic determinants are likely to be conformation‐dependent.

Bilirubin binding to myelin basic protein, histones and its inhibition in vitro of cerebellar protein synthesis

Summary The binding of unconjugated bilirubin to bovine CNS myelin basic protein and to lysine and arginine rich histones has been demonstrated by means of difference spectroscopy and circular dichroism spectroscopy. This is the first demonstration of a brain specific protein that can bind bilirubin and provides a mechanism for bilirubin retention in brain as well as a mechanism for interfering with the normal acidic lipid-basic protein binding interaction. The inhibition of protein synthesis in cerebellar homogenates by bilirubin has also been demonstrated. The inhibition is about 50 per cent in the presence of 100 μM bilirubin and 85 per cent in the presence of 700 μM bilirubin, These results require that the current mechanisms for bilirubin neurotoxicity and cytotoxicity be expanded to include the present findings.

Radioimmunological determination of myelin basic protein (MBP) and MBP-antibodies.

Optimal conditions for radioiodinating of MBP by the chloramine T method are described. Adsorption on CM cellulose was found to be the best way to separate ¹²⁵T-MBP from inorganic iodine. Iodination and purification can be performed in less than 30 min. The iodinated MBP was used for radioimmunological determination of antibodies against MBP and of MBP itself. The immunoreactivity of iodinated MBP was independent of the extent of iodination, by which an upper level of 8 radio iodine atoms/molecule could be reached. Therefore, it is possible to develop a radioimmunoassay of high sensitivity. The optimal conditions for formation of the antibody-MBP complex were investigated. The complex was isolated using gel filtration on Sephadex or dextran-coated charcoal. Both gave the same results, but the charcoal procedure is far more rapid. Antibody titration curves and MBP standard curves were performed. Bovine and human MBP, which differ from each other in molecular weight and amino acid sequence, were shown to give a complete cross-reaction with antibodies against human MBP. In a preliminary study in sera cerebrospinal fluids of patients with multiple sclerosis humural antibodies to human MBP could not be detected, whereas in serum of a patient with a second cerebrovascular accident MBP antibodies were found.

Myelination Inhibition Factor: Its Absence in Sera from Subhuman Primates Sensitized with Myelin Basic Protein

Abstract Experimental allergic encephalomyelitis was induced in subhuman primates by inoculation with either whole monkey brain plus Freund's adjuvant or with purified bovine myelin basic protein combined with Freund's adjuvant. Sera from the whole brain-sensitized primates, when incorporated into tissue culture nutrient medium and applied continuously to cerebellar cultures from the day of explantation on, prevented the formation of myelin in the explants. Sera from basic protein-sensitized primates, on the other hand, failed to inhibit myelination when applied in like fashion to cerebellar tissue cultures, confirming a previous demonstration of a similar lack of myelination-inhibiting activity in sera from basic protein-sensitized guinea pigs. The results suggest that the tissue culture myelination inhibition factor is induced by a component of whole central nervous system tissue other than the encephalitogenic protein.

Immunologic studies of acetylated encephalitogenic myelin basic protein.

SummaryRabbits were hyperimmunized with bovine myelin basic protein (BP) or its acetylated derivative (AcBP). The sera were studied by means of passive hemagglutination with formalinized, tannic acid-treated sheep erythrocytes coated with BP or AcBP. Formalin treatment eliminates the nonspecific clumping of BP-coated sheep cells, which we previously encountered. Sera were also analyzed by immunodiffusion in agarose. The rabbits immunized with BP produced antibodies which reacted equally well with BP and AcBP. However, the rabbits immunized with AcBP formed antibodies which were apparently directed against the acetyl group, in addition to anti-BP antibodies.