Isolation of human tumor antigens recognized by antibodies for development of immunotherapy and gene therapy

为了分离出用于食管癌、胰腺癌和结肠癌等多种癌症免疫治疗的人肿瘤抗原，我们采用SEREX方法，克隆表达DNA，分离编码肿瘤蛋白的cdna，并诱导肿瘤患者产生IgG抗体反应。利用黑色素瘤患者的血清和cDNA文库，分离出一种新的抗原KU-MEL1。除了培养的黑色素细胞外，该抗原在大多数正常组织中不表达，然而，它在大多数黑色素瘤细胞以及各种腺癌和鳞状细胞癌中表达。利用胰腺癌患者血清和cDNA文库分离到一种新的抗原KU-PAN1。除睾丸外，该抗原在大多数正常组织中不表达，但在一些胰腺癌、乳腺癌和结肠癌中表达。利用食管癌患者的血清和cDNA文库，分离出先前分离的癌睾丸抗原MAGE-A4。MAGE-A4可被CD8+ T细胞识别。利用结肠癌患者血清和cDNA文库分离EIF4和AHNAK核蛋白。本研究中鉴定的抗原特异性IgG抗体在不同癌症患者的一些血清中检测到，但在健康个体的血清中未检测到。利用膀胱癌患者血清和cDNA文库，分离到与凝集素同源的蛋白，在食管癌患者血清中检测到该抗原的IgG抗体。因此，这些新分离的肿瘤抗原可能有助于开发新的诊断方法以及各种癌症患者的免疫疗法。

To isolate human tumor antigens for immunotherapy of various cancers including esophageal, pancreatic and colon cancers, we applied the SEREX method, expression DNA cloning for the isolation of cDNAs encoding cancer proteins that could induce IgG antibody responses in patients with cancer. Using serum and cDNA library from a melanoma patient, a novel antigen KU-MEL1 was isolated. This antigen was not expressed in most normal tissues tested in the exception of cultured melanocytes, however, it was expressed in most melanoma cells as well as in various adonocarcinoma and squamous cell carcinoma. Using sera and cDNA library from patients with pancreatic cancer, a novel antigen KU-PAN1 was isolated. This antigen was not expressed in most normal tissues in the exception of testis, but expressed in some of the pancreatic, breast and colon cancers. Using sera and cDNA library from patients with esophageal cancer, previously isolated cancer-testis antigen, MAGE-A4, was isolated. MAGE-A4 was shown to be recognized by CD8+ T cells. Using sera and cDNA library from patients with colon cancer, EIF4 and AHNAK nucleoproteins were isolated. IgG antibodies specific for the antigens identified in the present study were detected in some sera from patients with various cancers, but not detected in sera from healthy individuals. Using sera and cDNA library from patients with bladder cancer, the protein homologous to ecalectin was isolated, and IgG antibody against this antigen was frequently detected in sera from patients with esophageal cancers. Therefore, these newly isolated tumor antigens may be useful for development of new diagnostic methods as well as immunotherapies for patients with various cancers.