Abstract Details

Title A Highly Sensitive Electrochemiluminescence (ECL) Immunoassay for Measurement of Amyloid Beta1-42 peptide in Human Plasma

Topic Aging, Dementia, and Behavioral Neurology

Presentation(s) P3 - Poster Session 3 (5:30 PM-6:30 PM)

Poster/Presentation
Number 9-027

Objective We hypothesized that a novel ECL immunoassay would be developed that is cost effective and sensitive enough to detect amyloid beta 1-42 (Aβ42) levels in plasma.

Background Aβ42 is associated with plaque formation in brain of patients with Alzheimer disease (AD). Studies have suggested that measurement of plasma Aβ42 has potential utility in clinical trials of Aβ lowering therapeutics. Commercial ELISAs are used to quantitate Aβ42 in CSF of AD. However, the assay is not sensitive enough to measure the low levels of plasma Aβ42, since the levels are near the lower limits of detection. Although sensitive assay like single molecule array (Simoa) has been developed, the high cost of the instrument and assay reagents limit its use in many academic centers.

Design/Methods We developed an ECL based sandwich ELISA using our high affinity rabbit monoclonal antibody (RabmAb) to Aβ42 (Miller et al. 2011) (Biolegend), and signal was amplified by Femto maximum sensitivity substrate (Thermo-Fisher). To demonstrate the sensitivity and clinical utility of the assay, we examined Aβ42 levels in 88 plasma (13 AD, 75±9 years old; 25 elderly controls, 71±9; 25 Down Syndrome (DS), 46±9 and 25 young controls, 45±7). Analyses were conducted using parametric or nonparametric statistics.

Results The measurement range of the assay using Aβ42 standards was .25-250 pg/ml. The limit of detection (background ±3SD) was 1 pg/ml. Intra-assay variability was <10%, and inter-assay was <20%. Aβ42 levels in AD (25.8±55.9 pg/ml) and controls (5.9±5.1) were similar. Levels were higher in DS (81.5±81.6) than controls (13.8±19.1) (p<.01). All AD, DS and 45 of 50 controls plasma showed detectable Aβ42.

Conclusions Our assay provided sensitivity to quantitate plasma Aβ42 in clinical samples. With the lower cost and availability of RabmAb to Aβ42, the assay is well-suited in many laboratories to quantitate Aβ42 as a potential plasma biomarker in clinical trials of AD.

Authors/Disclosures
Pankaj D. Mehta, PhD PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
Thomas M. Wisniewski, MD (New York University School of Medicine)	Dr. Wisniewski has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Frontiers in Aging Neuroscience. The institution of Dr. Wisniewski has received research support from the National Institute of Aging. Dr. Wisniewski has received intellectual property interests from a discovery or technology relating to health care.

��ɫ��

��ɫ��