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

• Published in: Journal of Immunology Research Vol. 2020; no. 2020; pp. 1 - 9
• Main Authors: Wang, Hong, Sringarm, Korawan, Sapbamrer, Ratana, Pattarawarapan, Mookda, Chantara, Somporn, Hongsibsong, Surat, Wongta, Anurak, Xu, Zhen-Lin
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 2020; Hindawi; John Wiley & Sons, Inc; Hindawi Limited
• Subjects: Advertising executives; Alpaca; Alzheimer Disease - diagnosis; Alzheimer Disease - urine; Alzheimer's disease; Amyloid beta-Peptides - urine; Antibodies; Antigens; Biomarkers; Cross Reactions; Cross-reactivity; Dementia disorders; Disease; Enzyme-Linked Immunosorbent Assay; Enzymes; Humans; Immunoassay; Immunoassay - methods; Immunoassay - standards; Immunology; Neurodegenerative diseases; Peptides; Polyclonal antibodies; Proteins; Reproducibility of Results; Sensitivity and Specificity; Urinalysis - methods; Urinalysis - standards; Urine; Viral antibodies; Thailand; China; Israel; United States > US
• ISSN: 2314-8861; 2314-7156
• DOI: 10.1155/2020/8821181

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 (IC50) 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.