Development and performance of a highly sensitive and specific two-site immunometric assay of calcitonin gene-related peptide.
Calcitonin gene-related peptide (CGRP), a potent endogenous circulating vasodilator, is produced by the alternative splicing of the calcitonin/CGRP gene and is expressed mainly in neural and cardiovascular tissues. We recently reported a highly sensitive radioimmunoassay of CGRP, based on an antiserum recognizing the C-terminus of the molecule. We have also found that circulating immunoreactive CGRP is heterogeneous; thus we are unable to measure selectively the intact molecule with our one-site competitive approach. We therefore attempted to construct a two-site immunometric assay involving two antibodies, one that detects the C-terminus and another that recognizes the midregion of the molecule. To enhance assay sensitivity, we applied a colorimetric amplification system to this assay. This rapid, robust, and reproducible assay provides more nearly accurate estimates of circulating CGRP and offers a sensitive and more specific alternative to the radioimmunoassay, with advantages in speed, simplicity, and convenience.
Department of Cellular and Molecular Sciences, St. George's Hospital Medical School, Tooting, London, U.K.
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M
Zaidi
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Seth
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Girgis
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CH
Self
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D006801:Humans; D007106:Immune Sera / Q000032:analysis; D007124:Immunoenzyme Techniques; D008969:Molecular Sequence Data; D011863:Radioimmunoassay; D051381:Rats; D015203:Reproducibility of Results
D007106:Immune Sera; D015740:Calcitonin Gene-Related Peptide