快速检测游离前列腺特异性抗原 ELISA 方法的建立

 目的 建立快速检测人血清中游离前列腺特异抗原（f-PSA）的 ELISA 方法。 方法 利用抗 f-PSA 的单克隆抗体（单抗）杂交瘤细胞株，一株单抗 2D1 用于固相包被，另一株单抗2E4进行辣根过氧化物酶标记，采用二步法，建立定量测定人血清 f-PSA 的双抗体夹心ELISA法。对该法的敏感度、精密度、准确性、特异性进行了分析。应用该法与瑞典 CanAg 公司的f-PSA ELISA 试剂盒同时检测了 18 例前列腺癌和 25 例前列腺增生患者血清标本的 f-PSA 含量，进行了两种方法检测结果的相关性分析。 结果 以双抗体夹心 ELISA 法检测 f-PSA，在 f-PSA 0 ~ 20 μg/L 范围内线性良好；敏感度为 0.025 μg/L；批内变异系数为 4.5% ~ 6.2%，批间变异系数为 3.9% ~ 7.2%；回收率为 94.3% ~ 111.1%；与 α1 抗糜蛋白酶结合的结合型PSA 交叉率为 0.7 %；检测 43 份临床标本 f-PSA 含量的结果与瑞典 CanAg 公司 f-PSA 试剂盒检测结果的相关系数为 0.995。 结论 所建立的双抗体夹心 ELISA 方法是一种特异、敏感、简便实用的 f-PSA 快速检测方法，有助于在 PSA 低水平升高的重叠范围内（4 ~ 10 μg/L）鉴别前列腺增生与前列腺癌。

Development of an ELISA for rapid detection of free prostate specific antigen

Objective To develop an ELISA for rapid and sensitive detection of free prostate specific antigen (f-PSA). Methods A sandwich ELISA was established by using two kinds of antibodies against f-PSA. McAb 2D1 was coated on a microtiter plate; and 2E4 was labeled with horseradish peroxidase (HRP). The specificity, sensitivity, precision, and accuracy of the ELISA were analyzed. The concentration of f-PSA in 43 serum samples collected from 18 patients with prostate cancer and 25 patients with benign prostate hypertrophies were detected by using the sandwich ELISA and CanAg Free PSA EIA kit (CanAg Diagnostics Inc, Sweden), respectively. The results were compared. Results The detection limit of the ELISA was 0.025 μg/L within an acceptable limit between 0 and 20 μg/L. The recovery rate of f-PSA ranged from 94.3% to 111.1%. The within-run and between-day coefficient of variation (CV) varied from 4.5% to 6.2% and 3.9% to 7.2%, respectively. It exhibited a cross-reactivity of 0.7% with PSA bound to α-1 antichymotrypsin (PSA-ACT). There was a good correlation between the results of f-PSA detection in 45 serum samples measured by the ELISA and CanAg Free PSA EIA kit (r = 0.995). Conclusions This sandwich ELISA is a rapid, sensitive and precise method in detecting f-PSA. In comparison with the commercial test kit of f-PSA, the ELISA was satisfying for its clinical applications. This method can be used to discriminate between benign and malignant prostate disease with a serum PSA level of 4－10 μg/L.