Molecular size of myelin basic protein immunoactivity in spinal fluid.

The molecular size of myelin basic protein (MBP) immunoactivity in spinal fluid from patients with multiple sclerosis, acute stroke or who had gone through neurosurgery was determined by gel filtration. Gel filtration fractions were analysed for MBP by radioimmunoassay. Spinal fluid from all patients demonstrated a broad range of MBP immunoactivity. The neurosurgery and stroke cases had high MBP immunoactivity in the higher molecular range, around 67 000 daltons. The spinal fluid from MS patients had increased levels of low molecular size MBP immunoactivity, around 10-13 000 daltons. The results suggest that different forms of demyelinating processes give rise to various kinds of MBP fragments and/or different proteolytic activity on MBP within the spinal fluid space.