An evaluation of a procedure for the isolation of myelin basic protein (BP)

A detailed description and stepwise evaluation of a procedure that can be used to obtain myelin basic protein (BP) from whole brain is presented. The procedure involved the 0.001 MHC1 extraction of whole brain pre-treated in a sequential manner with chloroform-methanol (2:1 v/v), acetone, and deionized water. This is followed by a precipitation of the extract at pH 9.0, and gel filtration of the supernatant in 0.01 M HC1. Yields of canine and porcine BP and their disc gel evaluations are presented at several key points in the procedure. The final products possessed a high degree of homogeneity when examined on SDS gels stained with commonly used protein stains. When compared with six SDS-gel marker-protein standards, the canine and porcine final products had mobilities that correspond to an apparent molecular weight of 18,5000 +/- 5%. Quantitative binding of 125I-labeled canine and porcine BPs with standardized rabbit anti-BP antisera gave comparable results. Immunoelectrophoretic and immunodiffusion examinations demonstrated single components and complete identity. The canine and porcine BP's also reacted fully with syngeneic anti-BP antisera raised in Lewis-strain rats. The canine BP was tested for encephalitogenicity in Lewis-strain rats and found to be comparable to rat BP in producing experimental allergic encephalomyelitis.