Abstract
Apolipoprotein‐E (Apo‐E) isoforms, especially the Apo‐E4 isoform, are considered to be genetic risk factors for familial as well as sporadic Alzheimer’s disease (AD). Using monoclonal antibodies specific for Apo‐E4 (MAb412‐1‐7) and Apo‐E (LZ18), we established a sandwich ELISA for the measurement of Apo‐E4 levels in serum. Total Apo‐E also was determined by sandwich ELISA with a second pair of monoclonal antibodies, LZ12 and LZ18. Estimation of a patient’s homozygous or heterozygous status for the Apo‐E4 isoform was subsequently calculated as the ratio of Apo‐E4/total Apo‐E, respectively. Although the antibody for Apo‐E used here does not have equivalent reactivity toward Apo‐E2, ‐E3, or ‐E4, we were able to attain a fairly reliable assay system to estimate the status of the Apo‐E4 isoform through a simple formula for the calculation of total Apo‐E versus Apo‐E4 isoform. J. Clin. Lab. Anal. 14:260–264, 2000. © 2000 Wiley‐Liss, Inc.
Keywords: sandwich ELISA, Apo‐E4 isoform, allelic status
REFERENCES
- 1. Lendon CL, Ashall F, Goate AM. 1997. Exploring the etiology of Alzheimer disease using molecular genetics. JAMA 277:825–831. [PubMed] [Google Scholar]
- 2. Selkoe DJ. 1994. Alzheimer’s disease: a central role for amyloid. J Neuropathol Exp Neurology 53:438–447. [DOI] [PubMed] [Google Scholar]
- 3. Cruts M, van Broeckhoven C. 1998. Presenilin mutations in Alzheimer’s disease. Hum Mutat 11:183–190. [DOI] [PubMed] [Google Scholar]
- 4. Hardy J. 1997. Amyloid, the presenilins and Alzheimer’s disease. Trends Neurosci 20:154–159. [DOI] [PubMed] [Google Scholar]
- 5. Corder EH, Saunders AM, Strittmatter WJ, et al. 1993. Gene dose of apolipoprotein E type 4 Allele and the risk of Alzheimer’s disease in late onset families. Science 261:921–923. [DOI] [PubMed] [Google Scholar]
- 6. Poirier J, Davignon J, Bouthillier D, Kogan S, Bertrand P, Gauthier S. 1993. Apolipoprotein E polymorphism and Alzheimer’s diseases. Lancet 342:697–699. [DOI] [PubMed] [Google Scholar]
- 7. Saunders AM, Strittmatter WJ, Schmechel D, et al. 1993. Association of apolipoprotein E allele ϵ4 with late‐onset familial and sporadic Alzheimer’s disease. Neurology 43:1467–1472. [DOI] [PubMed] [Google Scholar]
- 8. Mayeux R, Saunders AM, Shea S, et al. 1998. Utility of the apolipoprotein E genotype in the diagnosis of Alzheimer’s disease. New Engl J Med 338:506–511. [DOI] [PubMed] [Google Scholar]
- 9. Nukina N, Uchida K, Sakamoto T, Ide K, Kanazawa I. 1995. Monoclonal antibody against the polymorphic site distinguishes apolipoprotein E4 from other isoforms. Biochem Biophys Res Commun 216:467–472. [DOI] [PubMed] [Google Scholar]
- 10. Harvel RJ, Eder HA, Bragdon JH. 1955. The distribution and chemical composition of ultracentrifugally separated lipoproteins in human serum. J Clin Invest 34:1345–1353. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11. Kataoka S, Paidi M, Howard BV. 1994. Simplified isoelectric focusing/immunoblotting determination of apoprotein E phenotype. Clin Chem 40:11–13. [PubMed] [Google Scholar]
- 12. Poirier J, Delisle M‐C, Quirion R, et al. 1995. Apolipoprotein E4 allele as a predictor of cholinergic deficits and treatment outcome in Alzheimer disease. Proc Natl Acad Sci USA 92:12260–12264. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13. Strittmatter WJ, Saunders AM, Schmechel D, Pericak‐Vance M, Enghild J, Salvesen GS, Roses AD. 1993. Apolipoprotein E: high‐avidity binding to β‐amyloid and increased frequency of type 4 allele in late‐onset familial Alzheimer disease. Proc Natl Acad Sci USA 90:1977–1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14. Corder EH, Robertson K, Lannfelt L, et al. 1998. HIV‐infected subjects with the E4 allele for Apo‐E have excess dementia and peripheral neuropathy. Nat Med 4:1182–1184. [DOI] [PubMed] [Google Scholar]