亲和素放大促排在抗CEA单抗二步法预定位放免显像中的实验研究  

An experimental study of avidin chase in radioimmunoimaging with two-step pretargeting with anti-CEA monoclonal antibody

作　　者：李贵平[1] 朱承谟[2] 

机构地区：[1]第一军医大学南方医院核医学科,广东广州510515 [2]上海第二医科大学附属瑞金医院核医学科,上海200025

出　　处：《第一军医大学学报》2001年第2期118-120,共3页Journal of First Military Medical University

基　　金：上海市教委高校博士学科点建设基金

摘　　要：目的提高抗ＣＥＡ单抗二步法预定位放免显像的诊断效果。方法 荷人结肠癌裸鼠经尾静脉注射生物素化抗 ＣＥＡ单抗 １００μｇ，４８ ｈ后腹腔注射亲和素 ８０μｇ，０．５ ｈ再经腹腔注射１５３Ｓｍ标记的 ＳＡ ３．７ ＭＢｑ／１５μｇ（放大促排组）。以 二步法（生物素化ＣＥＡ单抗－１５３Ｓｍ标记链霉亲和素）和１５３Ｓｍ标记的ＣＥＡ单抗作为对照组。在注射放射性标记物后４ 和 ２４ ｈ进行体外 γ ＣＴ显像和体内标记物分布测定。结果亲和素放大促排组 ４ ｈ即见肿瘤部位浓聚放射性，而对照组 无明显显影。亲和素放大促排组瘤／血放射性比值在注药后 ４ ｈ和 ２４ ｈ分别为 １．５５±０．０５８和 ４．６２±１．０７６，高于对照组 （二步法组和直接标记法组分别为１．００４±０．２２１和２．０２８±０．３６７及０．２６０±０．０８４和０．８４７±０．３６８）。结论亲和素放大促排 能迅速降低血本底，提高靶／非靶（Ｔ／ＮＴ）放射性比值，缩短显像时间，改善显像质量。Objechve To promote the diagnostic efficacy of radioimmunoimaging with two-step pretargeting with anti-CEA monoclonal antibody by the employment of avidin chase. Methods Nude mice bearing human colonic tumor and labeled as avidin chase group were injected with biotinylated anti-CEA monoclonal antibody (mAb-Bt), 48 h after which avidin injection was performed followed by 153Sm-labeled streptavidin (SA) 30 min later. In the nude mice serving as two-step pretargeting group, avidin injection was omitted and in direct labeling group, neither 153Sm-SA nor avindin injection was performed, Four and 24 h after the injection, emission CT imaging biodistribution of 153Sm-SA were studied in the 3 groups and the results statistically analyzed. Results Clear visualization of the tumors was achieved 4 h after the injection of radiolabeled SA in avidin chase group and the tumor-to-blood radioactivity ratios at 4 and 24 h were l.549±0.058 and 4.623±1.076 respectivily, while those of two-step pretargeting group were l.004±0.221 and 2.028±0.367; in direct labeling group, the ratios were 0.260±0.084 and 0.847±0.368, respectively. The target-to-nontarget ratios of all organs in avidin chase group were also higher than those in the other 2 groups, in which the tumors were poorly visualized. Conclusion Avidin chase could increase the target-to-nontarget ratio, decrease the blood background and shorten the imaging time with improved imaging quality.

关 键 词：单克隆抗体 放射免疫显象 亲和素-生物素 肿瘤 裸鼠 抗CEA 

分 类 号：R730.4[医药卫生—肿瘤]