Qin H, Chen W, Takahashi M
Shanghai Medical University, Department of Immunology.
Zhonghua Zhong Liu Za Zhi. 1996 May;18(3):173-6.
Mutated p21 ras protein contains single substituted amino acid residue. It can be considered as cancer-specific protein. The current study examined whether T-cell and Ab responses to mutant p21 ras protein and/or peptide can be detected in patients with pancreatic or colon cancer. Studies focused on the aspartic acid substitution in amino acid position 12(ras D12) as the commonest mutation in gastrointestinal malignancy. IgA antibodies directed against mutated ras D12 protein were detected in 51 of 160 (31.8%) colon cancer patients, but only in 1 of 40 (2.5%) normals. The greater incidence of antibody in cancer patients provides evidence that immunization to the ras proteins occurred as a result of the malignancy. Seven of sixteen (43.7%) pancreas cancer patients responded to ras D12 peptide. T cell responses to ras D12 peptides were detected in only 2 of 25 (8.0%) colon cancer patients. None of the 11 normal individuals tested had positive responses to normal or mutant ras p21 proteins and/or peptides. Thus, Ab and CD4+ T cell immunity to the mutated segment of ras protein is present in some patients with gastrointestinal cancer.
突变的p21 ras蛋白含有单个取代的氨基酸残基。它可被视为癌症特异性蛋白。当前的研究检测了在胰腺癌或结肠癌患者中是否能检测到针对突变型p21 ras蛋白和/或肽的T细胞及抗体反应。研究聚焦于第12位氨基酸的天冬氨酸取代（ras D12），这是胃肠道恶性肿瘤中最常见的突变。在160例结肠癌患者中有51例（31.8%）检测到针对突变型ras D12蛋白的IgA抗体，但在40例正常人中仅有1例（2.5%）检测到。癌症患者中抗体发生率更高，这证明了针对ras蛋白的免疫反应是由恶性肿瘤引发的。16例胰腺癌患者中有7例（43.7%）对ras D12肽有反应。在25例结肠癌患者中仅有2例（8.0%）检测到对ras D12肽的T细胞反应。11例接受检测的正常个体中，无人对正常或突变型ras p21蛋白和/或肽有阳性反应。因此，一些胃肠道癌症患者存在针对ras蛋白突变片段的抗体和CD4 + T细胞免疫反应。
