A double antibody radioimmunoassay for myelin basic protein in cerebrospinal fluid.

Levels of myelin basic protein (MBP) in cerebrospinal fluid (CSF) are useful in assessing the extent of demyelination which has occurred, or is occurring, in a variety of human problems associated with demyelination. Thus, an accurate, specific, simple, and consistent test for detecting MBP in CSF is needed. We describe such a test herein. The radioimmunoassay (RIA) described is a double antibody RIA using human MBP, and rabbit anti-MBP as reagents. The test can be done using only 200 microL of unconcentrated CSF. The test was sensitive to 0.1 microgram MBP/L. Recovery of known amounts of MBP was 97-105%, the within-assay and between-assay reproducibility were excellent. The "normal range" for our MBP-RIA was less than 2 micrograms/L, with a "grey area" between 2.0 and 3.0 micrograms/L.