HER 2/Neu--A Target For Cancer Immunotherapy

描述(申请人提供)：本建议书的总体目标是 应用基于抗独特型(ID)的疫苗方法治疗 HER2/neu阳性的人类癌症。HER2/neu基因的扩增和/或过表达 发生在多种人类恶性肿瘤中，并与预后不良有关。 人源化抗HER2/neu单抗4D5(赫赛汀)给药时具有治疗作用 对于部分转移性乳腺癌患者，特别是在 与化疗相结合。这些令人振奋的结果为 进一步开发基于抗体的癌症治疗新策略。 一种这样的策略是主动特异性免疫疗法，在这种疗法中，宿主免疫 该系统针对表达HER2/neu的肿瘤细胞。我们建议开发 “内部图像”反ID疫苗，将类似于三维 HER2/neu的形状。用这样的抗-ID疫苗免疫将打破免疫 耐受性及诱导持续高效价HER2/neu抗体的研究 患者在遗传上不受限制的方式。我们将针对临床上的 Herceptin和mAb定义的HER2/neu已证实的保护性表位 520C9，识别不同的表位。鼠源单抗4D5(亲本抗体 Herceptin)和520C9将分别用作免疫抗体或 将生成反ID或AB2的ABI。AB2将被用来诱导 小鼠和兔的抗HER2/neu抗体(Abi‘)。两种物质的交叉反应 用天然的HER-2受体诱导的抗-抗-ID(Ab3)抗体将 用流式细胞术、免疫组织化学和免疫沉淀法测定 并以相应的ABI为阳性对照。抗肿瘤活性 Ab3(Abi‘)的活性将在体外和体内进行评估。我们将确定 AB3对HER2/neu阳性癌细胞的生长抑制作用 组织培养和裸鼠异种移植。细胞和分子 抗体诱导生长抑制的机制将被研究。这个 然后将测试潜在的抗ID疫苗的治疗效果 免疫功能正常的肿瘤的保护和治疗 转导HER2/neu基因的小鼠肿瘤细胞模型。 选定的抗-ID疫苗的免疫治疗潜力也将是 在HER2/neu转基因小鼠中进行评估。最优选择的标准 抗ID疫苗将基于激发抗肿瘤活动的能力 在体外和体内。这项研究将是临床试验的前奏。 HER2/neu阳性的癌症患者使用单一或联合抗ID疫苗。

DESCRIPTION (provided by applicant): The overall objective of this proposal is to apply an anti-idiotype (Id) based vaccine approach for the treatment of HER2/neu positive human cancer. Amplification and/or overexpression of HER2/neu occurs in multiple human malignancies and is associated with a poor prognosis. A humanized anti-HER2/neu mAb, 4D5 (Herceptin) is therapeutic when administered for a subset of patients with metastatic breast cancer, especially in combination with chemotherapy. These exciting results provide a basis for further development of new antibody-based cancer therapy strategies. One such strategy is active specific immunotherapy in which the host immune system is targeted to HER2/neu expressing tumor cells. We propose to develop "internal image" anti-Id vaccines that will resemble the three- dimensional shapes of HER2/neu. Immunization with such an anti-Id vaccine will break immune tolerance and induce sustained high titer HER2/neu specific antibodies in patients in a genetically unrestricted fashion. We will target the clinically proven, protective epitopes of HER2/neu as defined by Herceptin and also by mAb 520C9 which recognizes a different epitope. Murine mAb 4D5 (parental antibody for Herceptin) and 520C9 will be used separately as the immunizing antibody or Abi to which anti-Ids or Ab2 will be generated. Ab2 will be used to induce anti-HER2/neu antibodies (Abi') in mice and rabbits. The cross-reactivities of the induced anti-anti-Id (Ab3) antibodies with the native HER-2 receptor will be determined by flow cytometry, immunohistochemistry, and immunoprecipitation with the use of corresponding Abi as positive control. The anti-tumor activity of Ab3 (Abi') will be assessed both in vitro and invivo. We will determine the Ab3 mediated growth inhibitory effects on HER2/neu positive cancer cells in tissue culture and in xenografted nude mice. The cellular and molecular mechanisms of antibody-induced growth inhibition will be investigated. The therapeutic efficacy of the potential anti-Id vaccines will then be tested for tumor protection as well as therapy of established tumors in an immunocompetent murine model of carcinoma cells transduced with the HER2/neu gene. Immunotherapeutic potential of the selected anti-Id vaccines will also be evaluated in HER2/neu transgenic mice. The criteria for selection of optimal anti-Id vaccines will be based on the ability to invoke anti-tumor activities in vitro and invivo. This study will be a prelude to clinical trials for HER2/neu positive cancer patients with a single or combined anti-Id vaccine.