ANTIIDIOTYPE VACCINE THERAPY OF HUMAN COLORECTAL CANCER

我们已经产生了鼠单克隆抗独特型（抗体，3 H1，即癌胚抗原（CEA）的内部图像）。我们已经证明，晚期转移性结直肠癌（CRC）患者和高风险CRC患者在手术后的辅助设置产生了积极的免疫反应，对CEA后，足够数量的免疫与Chl抗Id吸附到氢氧化铝。我们证明了一个主要的IgG多克隆体液免疫反应与纯化的CEA和CEA阳性细胞介导的抗体依赖性细胞毒性的特异性结合。接种疫苗的患者还在抗Id 3 H1、CEA或衍生自3 H1和CEA的合成肽的存在下表现出体外T细胞增殖应答。虽然其中一名患者对3 H1具有客观临床应答，但几名患者继续疫苗治疗，疾病稳定12-36个月。毒性仅限于注射部位的局部反应，伴轻度发热。在本项目中，我们将进行临床试验，其中患有Dukes B和C结直肠癌的患者将用佐剂5 FU和亚叶酸以及抗Id 3 H1与不同的免疫佐剂如GS-21、GM-CSF或低剂量IL-2组合治疗。将观察患者的免疫应答和临床结局。将使用移植有人CEA转染的鼠结肠癌细胞系MC 38的C57 BL/6小鼠中的动物模型来开发利用抗Id 3 H1衍生物的更有效的免疫方法并剖析抗肿瘤免疫的机制。我们将研究3 H1的单链抗体分子（scFv）作为与多种佐剂和细胞因子混合的免疫原。我们将探讨树突状细胞（DC）在肿瘤免疫中的作用，在脉冲后，他们与相关的抗独特型试剂。此外，腺病毒载体（AdV）将用于将3 H1-scFv或CEA引入DC中，这反过来将被测试疫苗潜力。我们还将从CRC患者的白细胞分离产物（其中一些可能用3 H1疫苗预处理）中产生潜在的治疗性DC，并用抗Id 3 H1、CEA或相关肽脉冲它们或用表达这些基因的Adv转染它们，并在体外检测它们的抗原提呈和T细胞刺激功能或T细胞溶解功能。这些研究将是使用基于自体DC的抗Id疫苗和scFv对CRC患者进行临床试验的前奏。

We have generated a murine monoclonal anti-idiotype ( antibody, 3Hl, that is the internal image of the carcinoembryonic antigen (CEA). We have demonstrated that patients with advanced metastatic colorectal cancer (CRC) and patients with high risk CRC in the post-surgical adjuvant setting generate an active immune response against CEA following an adequate number of immunizations with the Chl anti-Id adsorbed to aluminum hydroxide. We demonstrated a predominantly IgG polyclonal humoral immune response with specific binding to purified CEA and CEA positive cells that mediated antibody-dependent cellular cytotoxicity. The vaccinated patients also demonstrated in vitro T cell proliferative responses in the presence of anti-Id 3Hl, CEA or synthetic peptides derived from 3H1 and CEA. While one of the patients had objective clinical response to 3Hl, several continue on vaccine therapy with stable disease from 12-36 months. Toxicity was limited to local reactions at the site of the injection with mild fevers. In this project, we will conduct clinical trials in which patients with Dukes B and C colorectal carcinoma will be treated with adjuvant 5FU and leucovorin and anti-Id 3Hl in combination with different immunologic adjuvants such as GS-21, GM-CSF or low-dose IL-2. The patients will be observed for immune responses and for clinical outcome. Animal models in C57BL/6 mice transplanted with the human CEA transfected murine colon cancer cell line MC38 will be used to develop more powerful methods of immunization utilizing the anti-Id 3Hl derivatives and to dissect the mechanisms of anti-tumor immunity. We will investigate a single chain Fv molecule (scFv) of 3Hl as an immunogen mixed with variety of adjuvants and cytokines. We will investigate the role of dendritic cell (DC) in developing tumor immunity after pulsing them with relevant anti-idiotypic reagents. In addition, adenoviral vectors (AdV) will be used to introduce 3H1-scFv or CEA into DC, which in turn will be tested for vaccine potential. We will also generate potentially therapeutic DC from leukapheresis products of CRC patients (some of them may be pretreated with 3H1 vaccine), and pulse them with the anti-Id 3Hl, CEA or relevant peptides or transduce them with Adv expressing these genes and examine their antigen presenting and T cell stimulatory function or T cell cytolytic function in vitro. These studies will be a prelude to clinical trials for CRC patients with autologous DC based anti-Id vaccine and scFv.