Fundamental and clinical research for esophageal cancer rejection peptide antigens as a vaccine therapy

我们研究了肿瘤特异性细胞毒性T淋巴细胞(CTL)在外周血中抗癌细胞的存在。取晚期癌症患者外周血单个核细胞(PBMC)，加入IL-2(100U/ml)培养约14天。培养后，从许多晚期食道癌患者的PBMC中识别出包括NK细胞和LAK细胞在内的主要CTL。这些CTL表达CD4阴性，CD8阳性。1991年Boon用CTL表达克隆方法对新的肿瘤排斥抗原基因进行了检测，发现了一个与人类白细胞抗原A24分子相关的新的肿瘤排斥基因MRP3。众所周知，MRP是一种多药耐药蛋白，通常许多肿瘤细胞都表达该蛋白。因此，MRP3多肽似乎是一种有用的肿瘤疫苗。我们使用面向CTL前体的肿瘤疫苗方法对晚期或复发的癌症患者进行了一项新的临床I期试验。为了在治疗前确定有效的多肽疫苗，患者的PBMC在体外通过14-癌疫苗的刺激进行检测。用一种新发明的方法在体外检测干扰素-γ的反应，评估大约需要2周的干扰素-γ的产生浓度。在14种肿瘤疫苗的I期试验中，许多病例的CTL前体增加，但由于肿瘤的严重进展，对极晚期食管癌患者没有临床效果。这一临床结果也在晚期胰腺癌或胃癌患者中发现。为了下一步的肿瘤疫苗研究，我们必须探索更有效的食道癌辅助和/或联合治疗方法。

We investigated the existence of cancer specific cytotoxic T lymphocytes (CTLs) against cancer cells in peripheral blood. Peripheral blood mononuclear cells (PBMC) sampled from advanced cancer patients were cultured with an addition of IL-2 (100U/ml) for about 14 days. Following the cultivation, predominant CTLs including NK cells and LAK cells were recognized in PBMC collected from many patients with advanced esophageal cancer. These CTLs expressed CD4 negative and CD8 positive. Using the CTL, new cancer rejection antigen gene was examined by expression cloning method presented by Boon in 1991.We found a new cancer rejection gene of MRP3 that connected to HLA-A24 molecule. MRP is well known as a multi drug resistant protein and usually many malignant cells express this protein. Therefore MRP3 peptide seems to be useful as a cancer vaccine.We performed a new clinical phase I trial for advanced or recurrent cancer patients using CTL precursor-oriented cancer vaccine method. To define the effective peptide vaccines prior to treatment, patients PBMC was examined by a stimulation of 14-cancer vaccine in vitro. hrimimoreaction was examined in vitro by a newly created method evaluating the concentration of IFN-gamma production that needs about 2 weeks. In the Phase I trial using 14 cancer vaccines, CTL precursor of many cases was increased but no clinical effect was found in patients with far advanced esophageal carcinoma due to severe progression of the cancer. This clinical result was also found in patients with advanced pancreatic cancer or gastric cancer. For the next study of cancer vaccine, we have to investigate about more effective adjuvant and/or combined therapy against esophageal carcinoma.