ANTIIDIOTYPE VACCINE THERAPY OF HUMAN COLORECTAL CANCER

我们产生了一种小鼠单克隆抗独特型抗体，3Hl，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患者在术后辅助治疗环境中，在使用氢氧化铝吸附的Chl抗- id进行足够数量的免疫接种后，会产生针对CEA的主动免疫应答。我们证明了IgG多克隆体液免疫应答主要与纯化CEA和CEA阳性细胞特异性结合，介导抗体依赖性细胞毒性。接种疫苗的患者在抗id 3Hl、CEA或由3H1和CEA衍生的合成肽存在下也表现出体外T细胞增殖反应。虽然其中一名患者对3Hl有客观临床反应，但有几名患者继续接受疫苗治疗，病情稳定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，我们将对Dukes B型和C型结直肠癌患者进行5FU辅助治疗和亚叶酸蛋白、抗id 3Hl联合不同免疫佐剂如GS-21、GM-CSF或低剂量IL-2的临床试验。将观察患者的免疫反应和临床结果。将人CEA转染小鼠结肠癌细胞系MC38移植至C57BL/6小鼠的动物模型将用于开发更有效的抗id 3Hl衍生物免疫方法，并探讨抗肿瘤免疫机制。我们将研究3Hl单链Fv分子（scFv）作为混合多种佐剂和细胞因子的免疫原。我们将研究树突状细胞（DC）在相关抗独特型试剂的脉冲作用下在肿瘤免疫中的作用。此外，将使用腺病毒载体（AdV）将3H1-scFv或CEA引入DC，然后对其进行疫苗潜力测试。我们还将从结直肠癌患者的白细胞分离产物（其中一些可能用3H1疫苗预处理）中产生具有潜在治疗作用的DC，并用抗id 3Hl、CEA或相关肽脉冲或用表达这些基因的Adv转导它们，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。这些研究将为基于自体DC的抗id疫苗和scFv在结直肠癌患者中的临床试验做铺垫。

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.