Detection of Proteins in Normal and Alzheimer's Disease Cerebrospinal Fluid with a Sensitive Sandwich Enzyme‐Linked Immunosorbent Assay

Abstract

Alzheimer's disease is a progressive degenerative dementia characterized by the abundant presence of neurofibrillary tangles in neurons. This study was designed to test whether the microtubule-associated protein tau, a major component of neurofibrillary tangles, could be detected in CSF. Additionally, we investigated whether CSF tau levels were abnormal in Alzheimer's disease as compared with a large group of control patients. We developed a sensitive sandwich enzyme-linked immunosorbent assay using AT120, a monoclonal antibody directed to human tau, as a capturing antibody. With this technique, the detection limit for tau was less than 5 pg/ml of CSF. Using AT8, which recognizes abnormally phosphorylated serines 199-202 in tau, the detection limit was below 20 pg/ml of CSF. However, with AT8, we found no immunoreactivity in CSF, suggesting that only a small fraction of CSF tau contains the abnormally phosphorylated AT8 epitope. Our results indicate that CSF tau levels are significantly increased in Alzheimer's disease. Also, CSF tau levels in a large group of patients with a diversity of neurological diseases showed overlap with CSF tau levels in Alzheimer's disease.

Phospho-tau/total tau ratio in cerebrospinal fluid discriminates Creutzfeldt–Jakob disease from other dementias

“…12 In addition, the CSF total tau content was measured by ELISA (Innotest hTau-Ag; Innogenetics, Ghent, Belgium) as described elsewhere. 13 All samples were run on three consecutive days. All statistical procedures were performed using the Statistical Package of the Social Sciences (SPSS) software.…”

Cerebrospinal fluid protein biomarkers for Alzheimer’s disease

“…As shown in Table 1, four different ELISA methods for quantification of T-tau have been published. [13][14][15][16] A moderate to marked increase in CSF T-tau in AD has consistently been found in numerous publications. 17 The first paper on CSF T-tau as a protein biomarker for AD used an ELISA method with a polyclonal reporter antibody and found a very marked increase in CSF T-tau in AD.…”

“…17 The first paper on CSF T-tau as a protein biomarker for AD used an ELISA method with a polyclonal reporter antibody and found a very marked increase in CSF T-tau in AD. 13 Subsequent studies used ELISA methods 14 -16 based on monoclonal antibodies that detect all isoforms of tau independently of phosphorylation state, and found increases in CSF T-tau of approximately 300% and 200%. 17 The CSF level of T-tau probably reflects the intensity of the neuronal damage and degeneration.…”

Proteolytic clearance of extracellular α-synuclein as a new therapeutic approach against Parkinson disease

“…34,35 It is secreted from cells by unconventional exocytosis or exosome [36][37][38] and its aggregates are taken up by cells via a hitherto unknown mechanism. 39 In addition, extracellular tau has been shown to be toxic to cultured neuronal cells, 40 and prion-like intercellular spreading of tau aggregates has been reported both in vivo and in vitro.…”