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

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.