Development of an Immunoassay for the Detection of Amyloid Beta 1-42 and Its Application in Urine Samples

Abstract

Amyloid beta peptides (Aβ1-42) have been found to be associated with the cause of Alzheimer’s disease (AD) and dementia. Currently, methods for detecting Aβ1-42 are complicated and expensive. The present study is aimed at developing an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to detect Aβ1-42 by using a polyclonal antibody from alpaca, an application used in urine samples. The serum was collected from the alpaca after immunizing it with Aβ1-42 at 500 μg/injection 5 times. The ic-ELISA was developed and showed a half-maximal inhibitory concentration ( I C 50 ) of 103.20 ng/ml. The limit of detection (LOD) was 0.39 ng/100 μl. The cross-reactivity was tested with Aβ1-40 and 8 synthesized peptides that had sequence similarities to parts of Aβ1-42. The cross-reactivity of Aβ1-40 and peptide 1 (DAEFRHDSGYE) was 55% and 69.4%, respectively. The ic-ELISA was applied to analyze Aβ1-42 in the urine and precipitated protein urine samples. This method can be used for detecting a normal level of total soluble Aβ (approximately 1 ng in 5 mg of precipitated urine protein) and can be used for detecting the early stages of AD. It is considered to be an easy and inexpensive method for monitoring and diagnosing AD.

Development of a plant-produced recombinant monoclonal antibody against Δ-9-tetrahydrocannabinol (Δ9-THC) for immunoassay application

“…The study showed major advantages, including a significant decrease in average analytical time and high specificity to the target [14] . According to Wongta, Hongsibsong [50] , the development of an immunoassay can be applied to detect amyloid beta peptides (A β 1–42), which are related to Alzheimer's disease (AD) and dementia, and it provides an alternative method to diagnose high-risk and early stages of AD with rapid and simple analysis. This method is related to the binding activity between the antibody and the antigen or analyte using enzyme-linked immunosorbent assays (ELISAs) [ 18 , 51 ].…”

Peptide-Based Vaccines for Neurodegenerative Diseases: Recent Endeavors and Future Perspectives

“…On the other hand, recent research efforts have focused on the discovery of novel biomarkers, eventually including personalized markers, for assessing onset and/or progression of neurodegenerative diseases [1,8,135]; diagnostic and/or prognostic biomarkers are especially needed in the area of synucleinopathies [14]. Moreover, much research has been recently directed toward developing improved analytical methods for reliable measurement of established biomarkers, each one alone or often in combination, in easily available biological fluids, such as plasma, urine, or saliva [1,[136][137][138]. Success in the discovery of novel biomarkers and development of highly reliable and easy to perform methods for biomarker analysis will definitely facilitate the evaluation of candidate peptide-based vaccines for neurodegenerative diseases and accelerate further progress.…”

“…The N-terminal α-syn(1-10) and C-terminal α-syn (90-140) fragments were found to be exposed with ELISA experiments [101]. On the other hand, the C-terminal epitopes α-syn(111-140)/α-syn (121)(122)(123)(124)(125)(126)(127)(128)(129)(130)(131)(132)(133)(134)(135)(136)(137)(138)(139)(140) were recognized by human anti-α-syn antibodies isolated from PD patients [102]. Moreover, the secondary structural features of α-syn in an aqueous environment have been studied with computer simulation [103].…”

Electrochemical Immunosensor for the Sensitive Detection of Alzheimer's Biomarker Amyloid‐β (1–42) Using the Heme‐amyloid‐β (1–42) Complex as the Signal Source

“…Currently, most measurements of Aβ 42 rely on immunoassay techniques, such as enzyme-linked immunoassays [40][41][42], which are time consuming. Various techniques have been attempted for the probing of Aβ 42 , such as resonance light scattering [43], surface-enhanced Raman spectroscopy (SERS) [44], and localized surface plasmon resonance (LSPR) [45,46], but these are less flexible, costly, and labour-intensive, requiring complex equipment.…”