Stenman U H, Leinonen J, Alfthan H, Rannikko S, Tuhkanen K, Alfthan O
Department I and II of Obstetrics and Gynecology, Helsinki University Central Hospital, Finland.
Cancer Res. 1991 Jan 1;51(1):222-6.
We have studied the forms of prostate-specific antigen (PSA) in serum of patients with prostatic cancer and benign prostatic hyperplasia. Fractionation of serum by gel filtration and assay of the fractions for PSA showed that a considerable part of the PSA immunoreactivity in serum consisted of complexes that were larger than PSA. The complexes were assayed by time-resolved immunofluorometric assays based on an antibody against PSA on the solid phase and europium-labeled antibodies against various protease inhibitors as indicator antibodies. In addition to its monomeric form, PSA was found to occur in complex with alpha 1-antichymotrypsin. The proportion of the alpha 1-antichymotrypsin complex was a major form of PSA and it increased with increasing PSA concentrations, being over 85% at PSA levels exceeding 1000 micrograms/liter. A complex with alpha 1-protease inhibitor was also observed in serum of patients with prostatic cancer and very high levels of PSA. Complexes with alpha 2-macroglobulin and inter-alpha-trypsin inhibitor were detected, but their concentrations were low and similar in sera of cancer patients, normal men, and normal women, suggesting that they were not prostate derived. Commercial immunoradiometric assays for PSA were found to measure free PSA and its complexes with alpha 1-antichymotrypsin but not the complexes with alpha 2-macroglobulin and inter-alpha-trypsin inhibitor. The proportion of the PSA-alpha 1-antichymotrypsin complex was higher in patients with prostatic cancer than in those with benign hyperplasia. Therefore, assay of the complex had a higher sensitivity for cancer than assay of total PSA immunoreactivity.
我们研究了前列腺癌和良性前列腺增生患者血清中前列腺特异性抗原（PSA）的形式。通过凝胶过滤对血清进行分级分离，并对各分级进行PSA检测，结果显示血清中相当一部分PSA免疫反应性由大于PSA的复合物组成。基于固相抗PSA抗体和铕标记的抗各种蛋白酶抑制剂抗体作为指示抗体，采用时间分辨免疫荧光分析法对这些复合物进行检测。除了单体形式外，还发现PSA以与α1 -抗糜蛋白酶形成复合物的形式存在。α1 -抗糜蛋白酶复合物的比例是PSA的主要形式，且随着PSA浓度的增加而升高，在PSA水平超过1000微克/升时超过85%。在前列腺癌患者且PSA水平非常高的血清中也观察到了与α1 -蛋白酶抑制剂的复合物。检测到了与α2 -巨球蛋白和α-胰蛋白酶抑制剂的复合物，但其浓度较低，在癌症患者、正常男性和正常女性的血清中相似，这表明它们并非源自前列腺。发现用于PSA的商业免疫放射分析法可检测游离PSA及其与α1 -抗糜蛋白酶的复合物，但不能检测与α2 -巨球蛋白和α-胰蛋白酶抑制剂的复合物。前列腺癌患者中PSA -α1 -抗糜蛋白酶复合物的比例高于良性增生患者。因此，检测该复合物对癌症的敏感性高于检测总PSA免疫反应性。
