Kayser Simone, Watermann Iris, Rentzsch Christine, Weinschenk Toni, Wallwiener Diethelm, Gückel Brigitte
Department of Gynecology and Obstetrics, University of Tübingen, Calwerstrasse 7, 72076, Tübingen, Germany.
J Cancer Res Clin Oncol. 2003 Jul;129(7):397-409. doi: 10.1007/s00432-003-0445-7. Epub 2003 Jun 26.
The absence of tumor-associated antigens (TAA) which might elicit an immune response is one reason for the disappointing results of therapeutical vaccines in cancer patients. Moreover, impaired expression of MHC class-I and components involved in antigen processing, such as TAP-1, -2, LMP-2, -7, and MECL-1, may lead to tumor escape from immune recognition. Expression profiling of TAA is one approach towards the design of well-defined and individualized anti-tumor vaccines.
Quantitative polymerase chain reaction (qRT-PCR) is the method of choice to characterize immunologically relevant properties of individual tumors. However, the application of qRT-PCR as a surrogate parameter for the expression of TAAs depends upon the assumption that the level of an mRNA species correlates with the cellular level of the protein it encodes. Therefore, we additionally analyzed TAA expression by immunofluorescence and T cell recognition.
In the present study we were unable to confirm that impaired TAP-1 or -2 (transporter associated with antigen processing) expression characterized at the mRNA level is an appropriate surrogate parameter for down-regulated MHC class-I expression in breast cancer. In addition, we analyzed the expression pattern of TAAs in breast and ovarian cancer cell lines. Besides the well-known over-expression of HER-2/neu, CEA, and MUC-1, multiple antigens of the MAGE-family were frequently co-expressed. We investigated whether detection of TAAs by qRT-PCR correlates with monoclonal antibody staining, and which method could predict T cell recognition. We demonstrated a correlation between tumor cell lysis by HLA-A*0201-restricted, MUC-1-specific CTL and threshold levels of MUC-1-specific mRNA.
MUC-1 is an example that TAA profiling by RT-PCR and flow cytometry can fail to correlate with each other and are of limited value in the prediction of T cell recognition.
缺乏可能引发免疫反应的肿瘤相关抗原（TAA）是治疗性疫苗在癌症患者中效果不佳的原因之一。此外，MHC I类分子以及参与抗原加工的成分（如TAP-1、-2、LMP-2、-7和MECL-1）表达受损，可能导致肿瘤逃避免疫识别。TAA的表达谱分析是设计明确且个体化抗肿瘤疫苗的一种方法。
定量聚合酶链反应（qRT-PCR）是表征单个肿瘤免疫相关特性的首选方法。然而，将qRT-PCR用作TAA表达的替代参数，依赖于这样一种假设，即mRNA种类的水平与其编码的蛋白质的细胞水平相关。因此，我们还通过免疫荧光和T细胞识别分析了TAA的表达。
在本研究中，我们无法证实，在mRNA水平上表征的TAP-1或-2（与抗原加工相关的转运蛋白）表达受损是乳腺癌中MHC I类分子表达下调的合适替代参数。此外，我们分析了乳腺癌和卵巢癌细胞系中TAA的表达模式。除了众所周知的HER-2/neu、CEA和MUC-1的过表达外，MAGE家族的多种抗原也经常共同表达。我们研究了通过qRT-PCR检测TAA是否与单克隆抗体染色相关，以及哪种方法可以预测T细胞识别。我们证明了HLA-A*0201限制性、MUC-1特异性CTL对肿瘤细胞的裂解与MUC-1特异性mRNA的阈值水平之间存在相关性。
MUC-1是一个例子，说明通过RT-PCR和流式细胞术进行的TAA分析可能彼此不相关，并且在预测T细胞识别方面价值有限。
