Luthman M, Jónsdóttir I, Skoog B, Wivall I L, Roos P, Werner S
Department of Endocrinology, Karolinska Hospital, Stockholm, Sweden.
Acta Endocrinol (Copenh). 1990 Sep;123(3):317-25. doi: 10.1530/acta.0.1230317.
A radioimmunoassay based on a monoclonal antibody. Mc-ab 1, which was raised against growth hormone but cross-reacted with human placental lactogen yielded higher GH immunoreactivity levels in serum than one based on a polyclonal antiserum. This discrepancy was noted in subjects with normal GH secretion as well as in patients with GH insufficiency. To characterize this GH immunoreactivity detected by Mc-ab 1, affinity purification and molecular sieve chromatography of serum were performed. High molecular weight proteins with GH immunoreactivity were found with both techniques. These proteins were associated with carbohydrates. Affinity cross-linking showed specific binding of radiolabelled GH to high molecular weight proteins in the serum. After fractionation of serum, the GH immunoreactivity became detectable by the polyclonal antiserum assay as well as by an immunoradiometric assay. GH immunoreactive material with an approximate mass of 80 kD was subjected to isoelectric focusing. When GH immunoreactive fractions at pH 5 were re-chromatographed, GH immunoreactivity was recovered in the elution volume corresponding to monomeric GH. Our results show that sera from normal subjects as well as from patients with deficient GH secretion contain notable amounts of high molecular weight GH which is undetectable by antibodies generally used for GH measurements, but which can be revealed after fractionation of serum.
一种基于单克隆抗体的放射免疫分析方法。抗生长激素产生的单克隆抗体Mc-ab 1与人胎盘催乳素发生交叉反应，与基于多克隆抗血清的方法相比，该方法检测血清中生长激素免疫反应性水平更高。在生长激素分泌正常的受试者以及生长激素分泌不足的患者中均发现了这种差异。为了表征由Mc-ab 1检测到的这种生长激素免疫反应性，对血清进行了亲和纯化和分子筛层析。两种技术均发现了具有生长激素免疫反应性的高分子量蛋白质。这些蛋白质与碳水化合物有关。亲和交联显示放射性标记的生长激素与血清中的高分子量蛋白质发生特异性结合。血清分级分离后，多克隆抗血清检测法和免疫放射分析法均可检测到生长激素免疫反应性。对质量约为80 kD的生长激素免疫反应性物质进行等电聚焦。当对pH 5时的生长激素免疫反应性组分进行再层析时，在与单体生长激素相对应的洗脱体积中恢复了生长激素免疫反应性。我们的结果表明，正常受试者以及生长激素分泌不足患者的血清中含有大量高分子量生长激素，一般用于生长激素测量的抗体无法检测到这些生长激素，但血清分级分离后可以检测到。
