Multiple sclerosis: sensitization of a myelin basic protein fragment (peptide T) encephalitogenic to primates. A preliminary report.

Myelin basic A1 protein is the sole antigen of the central nervous system capable of inducing experimental allergic encephalitis (EAE), but sensitization with peptide fragments of the molecule may also induce disease. Using the macrophage migration inhibition factor (MIF) assay we have compared sensitization to portions of the molecule active in inducing EAE in monkeys with results obtained concomitantly using the intact protein. Cellular sensitization to human myelin A1 protein, peptide L (residues 1-116), peptide T (residues 117-170), and petide Y (residues 154-170) was studied using the Thor-Rocklin MIF assay system. Lymphocytes of 10 normal subjects, 10 multiple sclerosis patients 0-3 weeks after onset, 10 4 weeks to 3 months after and 10 6 months or longer after onset of an acute exacerbation were assayed. Results of the investigation reveal evidence of cellular sensitization to myelin basic protein encephalitogenic peptide T occurring during attacks of multiple sclerosis. Peptide L, relatively nonencephalitogenic to primates, failed to induce a significant lymphocyte response, whereas peptide Y which is encephalitogenic gave irregular results.