Tode B, Messeri G, Bassi F, Pazzagli M, Serio M
Department of Clinical Physiopathology, University of Florence, Italy.
Clin Chem. 1987 Nov;33(11):1989-93.
To select the best tracer for use in a competitive immunoassay, we conjugated human somatomedin C (SmC) to various chemiluminescent compounds via two different synthetic pathways. Naphthylhydrazides and arylhydrazides, used as the labels, were incorporated via their imidate or their succinimide esters. Conjugating the carboxy terminal of (amino ethyl)ethyl-isoluminol to SmC via a succinimide linkage supplied the most sensitive detection limit and the most immunoreactive conjugate. We developed an immunoassay based on the use of this conjugate, and evaluated dextran-coated charcoal, second-antibody precipitation, and solid-phase immunoprecipitation for separating bound and free label. This chemiluminescent method has a detection limit of 16 pg per tube, and it is accurate and precise. Correlation studies with a conventional radioimmunoassay (x) for SmC gave the following regression equation: y = 0.66x + 3.76 (r = 0.953, n = 30); the slight discrepancies between the two methods are probably ascribable to the use of different antibodies. We thus propose this chemiluminescence immunoassay as an inexpensive and sensitive alternative to radioimmunoassay for measuring SmC in serum or in extracts of serum.
为了选择用于竞争性免疫测定的最佳示踪剂，我们通过两种不同的合成途径将人生长调节素C（SmC）与各种化学发光化合物偶联。用作标记的萘酰肼和芳酰肼通过它们的亚胺酯或琥珀酰亚胺酯引入。通过琥珀酰亚胺键将（氨基乙基）乙基异鲁米诺的羧基末端与SmC偶联，可提供最灵敏的检测限和免疫反应性最强的偶联物。我们基于该偶联物开发了一种免疫测定方法，并评估了葡聚糖包被的活性炭、第二抗体沉淀和固相免疫沉淀法用于分离结合型和游离型标记物。这种化学发光方法的检测限为每管16 pg，且准确、精密。与传统的SmC放射免疫测定法（x）进行相关性研究，得到以下回归方程：y = 0.66x + 3.76（r = 0.953，n = 30）；两种方法之间的细微差异可能归因于使用了不同的抗体。因此，我们建议将这种化学发光免疫测定法作为一种廉价且灵敏的替代方法，用于测定血清或血清提取物中的SmC，以替代放射免疫测定法。
