Sioud M, Hansen M H
Institute for Cancer Research, Department of Immunology, Molecular Medicine Group The Norwegian Radium Hospital, Oslo, Norway.
Eur J Immunol. 2001 Mar;31(3):716-25. doi: 10.1002/1521-4141(200103)31:3<716::aid-immu716>3.0.co;2-9.
Display on the surface of filamentous phages has been shown to be well suited for the enrichment of serum antibody-binding ligands. Here, we have taken the advantage of this technology to analyze the humoral immune response in patients with cancer. The cDNA repertoires from breast cancer cell lines T47D and MCF-7 were fused to the 3'-end of the filamentous phage M13 gene VI in all three reading frames. When the libraries were biopanned on rabbit polyclonal IgG against the human Bcl-x(L) protein, positive clones were selected, thus confirming the utility of the libraries. Using serum antibodies from patients with breast cancer, we specifically selected IgG-binding phage-encoded cDNA products. Sequence analysis of the selected clones identified important antigens including p53, centromere-F, int-2, pentraxin I, integrin beta5, cathepsin L2 and S3 ribosomal protein. The selected phage-displayed cDNA products were recognized by a significant number of breast cancer sera as compared to sera from normal individuals. Although the human pentraxin I mRNA was reported to be exclusively localized in the nervous system, we found it also expressed by breast cancer cell lines. Four out of 30 patients with breast cancer (13 %) showed reactivity with the recombinant pentraxin expressed in Escherichia coli, while no reactivity was found in normal sera. The obtained results demonstrate that phage display could be a valuable method for the identification of antigens recognized by the humoral immune system in patients with cancer.
丝状噬菌体表面展示已被证明非常适合富集血清抗体结合配体。在此，我们利用这项技术分析癌症患者的体液免疫反应。来自乳腺癌细胞系T47D和MCF-7的cDNA文库在所有三个阅读框中与丝状噬菌体M13基因VI的3'端融合。当文库用针对人Bcl-x(L)蛋白的兔多克隆IgG进行生物淘选时，阳性克隆被筛选出来，从而证实了文库的实用性。使用乳腺癌患者的血清抗体，我们特异性地筛选出与IgG结合的噬菌体编码cDNA产物。对所选克隆的序列分析鉴定出重要抗原，包括p53、着丝粒-F、int-2、五聚素I、整合素β5、组织蛋白酶L2和S3核糖体蛋白。与正常个体的血清相比，所选的噬菌体展示cDNA产物被大量乳腺癌血清识别。尽管据报道人五聚素I mRNA仅定位于神经系统，但我们发现它也在乳腺癌细胞系中表达。30例乳腺癌患者中有4例（13%）显示出与在大肠杆菌中表达的重组五聚素的反应性，而正常血清中未发现反应性。所得结果表明，噬菌体展示可能是一种有价值的方法，用于鉴定癌症患者体液免疫系统识别的抗原。
