Analysis of antigen to renal cell carcinoma and establishment of cancer specific antibody teratment

肾细胞癌（RCC）具有异质性临床表现，在初始诊断时高达30%的转移病例和30%的最初器官局限性病例在不同间隔的随访期间发生转移。近年来，针对特定分子的抗体已被应用于恶性疾病的临床治疗。尽管几种已经人源化的鼠单克隆抗体（mAb）成为针对少数恶性肿瘤的有用治疗剂，但由于我们缺乏对哪些抗原（Ag）可以成为有用靶标的了解，治疗性Ab还不能用于大多数人类癌症。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，我们分离了大量的人单克隆抗体，结合到RCC细胞表面。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，并通过质谱鉴定。我们分离了357个具有独特序列的mAb，并鉴定了7个不同的mAb。Ags在几种癌中高度表达。在制备完整的IgG1 Ab后，进行抗体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IgG1的mAb显示出有效的ADCC以及体内肿瘤活性。因此，在我们的研究中采用的程序，使我们能够成功地在全面鉴定肿瘤相关抗原（TAAs），并同时分离的单克隆抗体对RCC。因此，我们相信在可预见的将来，一些检测到的Ag将成为肿瘤治疗的有用靶点，并且一些mAb将成为RCC的有用治疗剂。

Renal cell cancer (RCC) has a heterogeneous clinical presentation with up to 30% metastatic cases at initial diagnosis and 30% of initially organ-confined cases developing metastases during follow-up at variable intervals. Recently antibodies against specific molecules have been applied for clinical treatment to malignant diseases. Although several murine monoclonal antibodies (mAbs) which have been humanized became useful therapeutic agents against a few malignancies, therapeutic Abs are not yet available for the majority of the human cancers due to our lack of knowledge 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 RCC 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 mass spectrometry. We isolated 357 mAbs with unique sequences and identified 7 distinct. Ags highly expressed on several carcinomas. After preparing complete IgGi Abs the in vitro assay for antibody-dependent cell-mediated cytotoxicity (ADCC) and the in vivo assay in cancer-bearing athymic mice were performed to examine anti tumor activity. The mAbs converted to IgG1 revealed effective ADCC as well as and tumor activity in vivo. Thus, the procedure adopted in our study enabled us to succeed in comprehensive identification of tumor-associated antigens (TAAs) and simultaneous isolation of mAbs against RCC. Therefore, we believe that some Ags detected will be useful targets for cancer therapy and several mAbs will become useful therapeutic agents to RCC in the foreseeable future.