Conry R M, LoBuglio A F, Loechel F, Moore S E, Sumerel L A, Barlow D L, Pike J, Curiel D T
University of Alabama at Birmingham, Comprehensive Cancer Center, L.B. Wallace Tumor Institute-249, 35294-3300, USA.
Cancer Gene Ther. 1995 Mar;2(1):33-8.
We have constructed a plasmid DNA encoding the full-length complementary DNA for human carcinoembryonic antigen (CEA) under transcriptional regulatory control of the cytomegalovirus early promoter/enhancer (pCEA) and demonstrated that this plasmid can function as a polynucleotide vaccine to elicit a CEA-specific immune response. This immune response protects against tumor challenge with syngeneic CEA-transduced colon carcinoma cells in mice. In the present work, the pCEA construct and purification method were modified to eliminate nonessential viral sequences, the ampicillin selectable marker, mutagens, and endotoxin to produce a reagent suitable for human clinical trials. The human use plasmid (pGT37) directs CEA expression at levels comparable with the original pCEA plasmid and can be propagated to yield large quantities of plasmid DNA based on kanamycin selection. A simple extraction technique greatly reduces contamination by endotoxin. Six weekly intramuscular injections of pGT37 elicited CEA-specific lymphoblastic transformation and antibody response in five of five mice and fully protected 10 of 10 mice against tumor challenge with syngeneic CEA-expressing colon cancer cells 42 days from the first plasmid injection. Thus, pGT37 encoding a tumor-associated antigen (CEA) has been shown to elicit cellular and humoral immune responses and mediate antitumor effects in vivo. This plasmid is suitable for human use and can be easily propagated in the laboratory.
我们构建了一种质粒DNA，其在巨细胞病毒早期启动子/增强子（pCEA）的转录调控下编码人癌胚抗原（CEA）的全长互补DNA，并证明该质粒可作为多核苷酸疫苗引发CEA特异性免疫反应。这种免疫反应可保护小鼠免受同基因CEA转导的结肠癌细胞的肿瘤攻击。在本研究中，对pCEA构建体和纯化方法进行了改进，以去除非必需的病毒序列、氨苄青霉素选择标记、诱变剂和内毒素，从而生产出适合人类临床试验的试剂。人用质粒（pGT37）指导CEA的表达水平与原始pCEA质粒相当，并且基于卡那霉素选择可大量繁殖以产生大量质粒DNA。一种简单的提取技术极大地减少了内毒素污染。每周一次，共六次肌肉注射pGT37，在五只小鼠中的五只中引发了CEA特异性淋巴细胞转化和抗体反应，并在首次注射质粒42天后，完全保护了十只小鼠中的十只免受同基因表达CEA的结肠癌细胞的肿瘤攻击。因此，编码肿瘤相关抗原（CEA）的pGT37已被证明可在体内引发细胞免疫和体液免疫反应并介导抗肿瘤作用。该质粒适合人类使用，并且可以在实验室中轻松繁殖。
