抗肺癌单抗的制备及其在肿瘤放免显象中的应用

Preparation of McAb against Lung Cancer and Its Application in Tumor Radioimmunoimaging

以肺鳞癌细胞为免疫原制备出抗肺癌单抗SM-1。免疫组织化学染色证明，其与各型肺癌均有较强结合力，而同其他组织肿瘤及正常组织则无明显突又反应。用两种蛋白水解酶将单抗高效消化成具有免疫活性的片段并经动物实验证明，完整抗体及片段均能特异性地分布于肿瘤组织并能使裸鼠移植瘤清晰地显象。片段与完整抗体相比，具有分布快、非特异性本底低及显象时间早的优点，显家质量也优于完整抗体。单抗用直接法标记99mT。试用于18例肺癌患者，有13例发现肿瘤病灶，阳性率为73％。

Objective In order to tracing the lung cancer, A monoclonal antibody was produced.Method The McAb, named SM-1,was specifically reacted with lung cancer confirmed by the immunopathological studies, then the McAb was digested into fragments by ficin and bromelain proteases. Results Both of the enzymatic methods were very effective and the immuno-reactivity of fragments was retained well. In our localization experiments, the T/ NT ratio revealed that radioiodinated McAb and fragments could be specifically uptaked by the tumour tissue and the T/NT ratio was higher in fragments group than intact IgG. After injection of 131I-IgG and fragments, the xenografts of human lung cancer bearing in nude mice were visualized distinctly during 36 - 48 hrs. Eighteen patients with lung cancer received Tc-99m labeled McAb intravenously. 13 cases showed radioactive accumulation in the foci of tumours. Conclusion These preliminary results suggested that SM-1 and its fragments might be a potential agents for radioimmunoimaging diagnosis of lung cancer.