THE ENCEPHALOMYELITIC ACTIVITY OF MYELIN ISOLATED BY ULTRACENTRIFUGATION

Abstract

A procedure for the isolation of myelin from whole guinea pig brain is described and evidence is presented that the encephalitogenic activity of nervous tissue is associated with it Electron microscopy was used to confirm its identity and to yield qualitative information regarding its purity. Bio-assay was carried out in the homologous species under optimal conditions for the quantitative estimation of encephalitogenic activity. The specific activity of myelin was found to be 5 times that of the tissue from which it was derived. A highly purified, encephalitogenic basic protein, previously isolated from whole brain, was isolated from the myelin fraction, confirming the locus of this protein in the myelin. The encephalitogenic basic protein was shown not to be a nuclear histone. One [mu]g of this basic protein induced allergic encephalo-myelitis in guinea pigs comparable to the disease induced by 100 [mu]g of lyophilized whole brain.