Krichevsky A, Armstrong E G, Schlatterer J, Birken S, O'Connor J, Bikel K, Silverberg S, Lustbader J W, Canfield R E
Department of Pathology, Columbia University College of Physicians and Surgeons, New York, New York 10032.
Endocrinology. 1988 Jul;123(1):584-93. doi: 10.1210/endo-123-1-584.
hCG is a glycoprotein hormone composed of two dissimilar subunits (alpha and beta) and is normally synthesized by trophoblastic tissue. Its measurement by immunoassay is widely employed as a test for pregnancy, but can be complicated by cross-reactivity with human (h) LH. Immunoassays based on the beta-subunit of hCG have been employed to decrease this cross-reactivity with hLH, but when these assays are used with urine specimens, the antibodies employed also detect a fragment of hCG beta, which can lead to significant differences in measurement. To overcome these problems, we have developed a series of monoclonal antibodies to the beta fragment of hCG recovered from pregnancy urine. Some of the antibodies that bind to this beta fragment are directed to a region of hCG beta that is different from the epitopes recognized by antibodies raised against the intact beta-subunit. The new epitopes available in the hCG beta fragment form the basis for novel immunoassays. These beta fragment antibodies are used in conjunction with other antibodies, directed to different epitopes of the hormone, to produce a series of immunoradiometric assays that can discriminate among intact hormone, free hCG beta, and hCG beta fragment. The hCG beta fragment antibodies described herein have affinities between 10(9) and 10(11) M-1 for the beta fragment and exhibit varying degrees of discrimination between the hCG beta fragment, the beta-subunits of hCG and hLH, and intact hCG and hLH.
人绒毛膜促性腺激素（hCG）是一种由两个不同亚基（α和β）组成的糖蛋白激素，通常由滋养层组织合成。通过免疫测定法对其进行检测被广泛用作妊娠试验，但可能会因与人促黄体生成素（hLH）的交叉反应而变得复杂。基于hCGβ亚基的免疫测定法已被用于减少与hLH的这种交叉反应，但当这些测定法用于尿液标本时，所使用的抗体也会检测到hCGβ的一个片段，这可能导致测量结果出现显著差异。为了克服这些问题，我们开发了一系列针对从妊娠尿液中回收的hCGβ片段的单克隆抗体。一些与该β片段结合的抗体针对的是hCGβ的一个区域，该区域与针对完整β亚基产生的抗体所识别的表位不同。hCGβ片段中可用的新表位构成了新型免疫测定法的基础。这些β片段抗体与针对该激素不同表位的其他抗体结合使用，以产生一系列免疫放射测定法，这些方法可以区分完整激素、游离hCGβ和hCGβ片段。本文所述的hCGβ片段抗体对β片段的亲和力在10⁹至10¹¹ M⁻¹之间，并且在hCGβ片段、hCG和hLH的β亚基以及完整hCG和hLH之间表现出不同程度的区分能力。
