Comprehensive screening for antigens overexpressed on carcinomas via isolation of human mAbs that may be therapeutic
Comprehensive screening for antigens overexpressed on carcinomas via isolation of human mAbs that may be therapeutic
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DOI：
10.1073/pnas.0712202105
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发表时间：
2008-05-20
影响因子：
11.1
通讯作者：
Kurosawa, Yoshikazu
中科院分区：
文献类型：
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作者：
Kurosawa, Gene;Akahori, Yasushi;Kurosawa, Yoshikazu
虽然几种鼠单克隆抗体已被人源化成为有用的治疗剂，对一些恶性肿瘤，治疗性抗体尚未获得大多数的人类癌症，因为我们缺乏知识的抗原（Ag）可以成为有用的目标。在本研究中，我们建立了一个程序，通过广泛分离的人单克隆抗体，可能成为治疗的全面鉴定这样的抗原。利用噬菌体展示抗体库，我们分离了大量与肿瘤细胞表面结合的人单克隆抗体。通过免疫染色对它们进行单独筛选，并选择优先和强烈染色恶性细胞的克隆。通过免疫沉淀分离这些克隆识别的Ag，并通过MS鉴定。我们分离了2，114个具有独特序列的mAb，并鉴定了21个在几种癌中高度表达的不同Ag。在这2，114种mAb中，356种特异性结合21种Ag之一。制备完整IgG（1）Ab后，进行Ab依赖性细胞介导的细胞毒性（ADCC）的体外测定和荷癌无胸腺小鼠中的体内测定以检查抗肿瘤活性。转化为IgG 1的mAb显示出有效的ADCC以及体内抗肿瘤活性。由于21个抗原中有一半表现出不同的肿瘤特异性表达模式，并且所分离的单克隆抗体表现出与抗原具有强亲和力的各种特性，因此所检测到的一些抗原可能成为相应肿瘤治疗的有用靶点，并且一些单克隆抗体可能成为治疗剂。
Although several murine mAbs that have been humanized became useful therapeutic agents against a few malignancies, therapeutic Abs are not yet available for the majority of the human cancers because of our lack of knowledge of which antigens (Ags) can become useful targets. In the present study we established a procedure for comprehensive identification of such Ags through the extensive isolation of human mAbs that may become therapeutic. Using the phage-display Ab library we isolated a large number of human mAbs that bind to the surface of tumor cells. They were individually screened by immunostaining, and clones that preferentially and strongly stained the malignant cells were chosen. The Ags recognized by those clones were isolated by immunoprecipitation and identified by MS. We isolated 2,114 mAbs with unique sequences and identified 21 distinct Ags highly expressed on several carcinomas. Of those 2,114 mAbs 356 bound specifically to one of the 21 Ags. After preparing complete IgG(1) Abs the in vitro assay for Ab-dependent cell-mediated cytotoxicity (ADCC) and the in vivo assay in cancer-bearing athymic mice were performed to examine antitumor activity. The mAbs converted to IgG1 revealed effective ADCC as well as antitumor activity in vivo. Because half of the 21 Ags showed distinct tumor-specific expression pattern and the mAbs isolated showed various characteristics with strong affinity to the Ag, it is likely that some of the Ags detected will become useful targets for the corresponding carcinoma therapy and that several mAbs will become therapeutic agents.