Abstract
A unique type of radioimmunoassay is described that does not require centrifugation or separation. Microbeads containing a fluorophor are covalently linked to antibody. When an 125I-labeled antigen is added it binds to the beads and, by its proximity, the emitted short-range electrons of the 125I excite the fluorophor in the beads. The light emitted can be measured in a standard scintillation counter. Addition of unlabeled antigen from tissue extracts displaces the labeled ligand and diminishes the fluorescent signal. Application of scintillation proximity immunoassay to tissue enkephalins, serum thyroxin, and urinary morphine is described. Applications of the principle to study the kinetics of interaction between receptors and ligands are discussed.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Berson S. A., Yalow R. S. General principles of radioimmunoassay. Clin Chim Acta. 1968 Sep;22(1):51–69. doi: 10.1016/0009-8981(68)90247-7. [DOI] [PubMed] [Google Scholar]
- Furth M. E., Davis L. J., Fleurdelys B., Scolnick E. M. Monoclonal antibodies to the p21 products of the transforming gene of Harvey murine sarcoma virus and of the cellular ras gene family. J Virol. 1982 Jul;43(1):294–304. doi: 10.1128/jvi.43.1.294-304.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Garattini E., Margolis J., Heimer E., Felix A., Udenfriend S. Human placental alkaline phosphatase in liver and intestine. Proc Natl Acad Sci U S A. 1985 Sep;82(18):6080–6084. doi: 10.1073/pnas.82.18.6080. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gruner S. M., Kirk G., Patel L., Kaback H. R. A method for rapid, continuous monitoring of solute uptake and binding. Biochemistry. 1982 Jun 22;21(13):3239–3243. doi: 10.1021/bi00256a033. [DOI] [PubMed] [Google Scholar]
- Hart H. E., Greenwald E. B. Scintillation proximity assay (SPA)--a new method of immunoassay. Direct and inhibition mode detection with human albumin and rabbit antihuman albumin. Mol Immunol. 1979 Apr;16(4):265–267. doi: 10.1016/0161-5890(79)90065-8. [DOI] [PubMed] [Google Scholar]
- Lahm H. W., Gerber L. D., Brink L., Kilpatrick D. L., Udenfriend S. Specific polyclonal antibodies to the carboxyl terminus of [Met]enkephalin-Arg6-Gly7-Leu8. Arch Biochem Biophys. 1983 Sep;225(2):422–429. doi: 10.1016/0003-9861(83)90049-8. [DOI] [PubMed] [Google Scholar]