A relatively simple preparation of guinea pig brain myelin, free of gross contamination by other cellular elements has been described. Electron microscopic evidence of the predominance of membranous (lamellar) forms was used as the criterion of purity of this fraction. The slight mitochondrial contamination of the myelin fraction was confirmed by its low succinic dehydrogenase activity. Quantitative bio-assay of the encephalitogenic activity of myelin showed it to have a higher specific activity than whole guinea pig brain. The low encephalomyelitic activity of the other subcellular constituents (nuclei and mitochondria) which were removed from myelin by ultracentrifugation in 30 per cent sucrose could be explained by a small amount of myelin contamination. A basic protein of high specific encephalitogenic activity has been isolated from myelin by methods previously applied to whole brain. Although the protein is similar to nuclear histones, the following facts point to certain significant differences. Nuclei prepared by a different procedure from the one developed for the isolation of myelin were found to be non-encephalitogenic. Although basic protein could be extracted readily from these nuclei by dilute HCl, the same extraction procedure yielded little extractable protein from whole myelin. Myelin which had been defatted by cold chloroform-methanol yielded a basic protein which was highly encephalitogenic. The evidence presented thus supports the view that there exists in myelin a new basic protein responsible for the induction of experimental allergic encephalomyelitis, which is distinctly different from nuclear histones. The possible relationship of this protein to myelin structure and function has been discussed.

Animals↗

PubMed1962

Prevention of experimental allergic encephalomyelitis (EAE) by vitamin C deprivation.

Scorbutic guinea pigs injected with CNS and mycobacterium to induce experimental allergic encephalomyelitis (EAE) showed no clear-cut neurological signs and failed to show histological evidence of central nervous system damage. The degree of protection afforded by vitamin C deprivation was related directly to the duration of the scorbutogenic diet and inversely to the strength of the CNS challenge. Vitamin C deprivation also abolished tuberculin sensitivity as measured by the PPD skin reaction. Upon restoration of vitamin C, the animals recovered their sensitivity to PPD but did not develop EAE. It was further demonstrated that these effects of vitamin C deprivation were not related to inanition or to the endogenous levels of 17-hydroxycorticosteroids.

Animals↗