<b>SENSITIVE ENZYME IMMUNOASSAY FOR S-100 PROTEIN: DETERMINATION IN HUMAN CEREBROSPINAL </b><b>FLUID </b>

Highly sensitive enzyme immunoassay method for measuring S-100 protein is described.The assay system was composed of the silicone rubber solid-phase with immobilized (anti-S-100 protein) antibody F(ab')2 fragments and the antibody Fab' fragments labeled with )6-D-galactosidase from Esc/ierz'c/iia co/1'.The antibody fragments were prepared from the immunoglobulin G (IgG) fractions of antiserum.The assay was highly sensitive for specific measurement of S-100 protein with a minimum measurable sensitivity of 3 pg, and the concentration of S-100 protein in human cerebrospinal fluid (CSF) could be determined.The CSF levels of S-100 protein in various patients correlated well with those of nervous system-specific enolase (NSE), which were also determined with a similar enzyme immunoassay method.CSF samples from patients with glioblastoma and hydrocephalus contained high levels of both S-100 protein and NSE.