Development of an Immunoassay for the Detection of Amyloid Beta 1-42 and Its Application in Urine Samples.
Anurak Wongta, Surat Hongsibsong, Somporn Chantara, Mookda Pattarawarapan, Ratana Sapbamrer, Korawan Sringarm, Zhen-Lin Xu, Hong Wang
Author Information
Anurak Wongta: Environmental Science Ph.D. Program, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. ORCID
Surat Hongsibsong: Environmental Science Ph.D. Program, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. ORCID
Somporn Chantara: Environmental Chemistry Research Laboratory, Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. ORCID
Mookda Pattarawarapan: Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. ORCID
Ratana Sapbamrer: Department of Community Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand. ORCID
Korawan Sringarm: Cluster of Research and Development of Pharmaceutical and Natural Products Innovation for Human or Animal, Chiang Mai University, Chiang Mai 50200, Thailand. ORCID
Zhen-Lin Xu: Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China. ORCID
Hong Wang: Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China.
Amyloid beta peptides (A1-42) have been found to be associated with the cause of Alzheimer's disease (AD) and dementia. Currently, methods for detecting A1-42 are complicated and expensive. The present study is aimed at developing an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to detect A1-42 by using a polyclonal antibody from alpaca, an application used in urine samples. The serum was collected from the alpaca after immunizing it with A1-42 at 500 g/injection 5 times. The ic-ELISA was developed and showed a half-maximal inhibitory concentration (IC) of 103.20 ng/ml. The limit of detection (LOD) was 0.39 ng/100 l. The cross-reactivity was tested with A1-40 and 8 synthesized peptides that had sequence similarities to parts of A1-42. The cross-reactivity of A1-40 and peptide 1 (DAEFRHDSGYE) was 55% and 69.4%, respectively. The ic-ELISA was applied to analyze A1-42 in the urine and precipitated protein urine samples. This method can be used for detecting a normal level of total soluble A (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.
References
Science. 1990 Oct 12;250(4978):279-82
[PMID: 2218531]
