title: A specific and sensitive ELISA for measuring S-100b in cerebrospinal fluid.
abstract: A sensitive, simple and specific sandwich ELISA for S-100b is described. This method involves the binding of a monoclonal anti-S-100b antibody to the wall of a microtitre plate. This capture antibody is subsequently incubated with S-100b standard, control or patient sample in the form of cerebrospinal fluid (CSF). After incubation, the microtitre plate is washed and horseradish peroxidase-labelled polyclonal anti-S-100b is added (detector antibody). The amount of detector antibody bound to the microtitre plate is proportional to the amount of S-100b in the sample. The assay has a lower limit of detection of 0.04 ng/ml and shows < 0.006% reactivity with the closely related polypeptide S-100a. The assay has a mean within-batch precision of 9.3 and 5.6% at S-100b concentrations of 0.38 and 0.8 ng/ml, respectively. The between batch precision is 8.9 and 8.1% at S-100b concentrations of 0.12 and 0.34 ng/ml, respectively. The recovery of S-100b from CSF spiked with 0.5 ng/ml was 94% with a CV of 8.5%. The assay may be completed in less than 5 h using precoated microtitre plates, thus lending itself to routine use in clinical laboratories. Using this ELISA, 154 CSF samples were analysed and 19% of samples were found to have elevated levels. The highest levels were found in patients with cerebral haemorrhage or central nervous system malignancy. S-100b concentrations from individuals without evidence of neurological disease were found to be less than 0.4 ng/ml. Only 5% of patients with multiple sclerosis were found to have elevated CSF S-100b concentrations. Serial CSF samples taken from a patient with an infected in-dwelling shunt showed a dramatic decline, suggesting that S-100b is rapidly cleared.
authors.affiliation: Department of Neuroimmunology, National Hospital for Neurology and Neurosurgery, London, UK. skgtejt@ion.bpmf.ac.uk
authors.forename: A J
authors.initials: AJ
authors.lastname: Green
authors.forename: G
authors.initials: G
authors.lastname: Keir
authors.forename: E J
authors.initials: EJ
authors.lastname: Thompson
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000134:cerebrospinal fluid*; D012680:Sensitivity and Specificity
chemical_list: D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins