前列腺酸性磷酸酶在胃癌中的表达及其体外诱导抗胃癌免疫应答

目的检测前列腺酸性磷酸酶(PAP)在胃癌中的表达水平,探讨PAP作为胃癌主动免疫治疗新靶点的可能性。方法分别用RT-PCR和Western blot方法检测胃癌细胞系中PAP mRNA和PAP蛋白的表达;用免疫组织化学方法检测胃癌组织中PAP的表达。利用PAP表位肽对胃癌患者的PBMCs进行体外诱导,ELISA法检测PAP特异性IFN-γ分泌水平;51Cr释放法检测CTLs的细胞毒活性。结果3种胃癌细胞(MKN-7、MKN-28和MKN-45)表达PAP mRNA,其中MKN-28和MKN-45表达PAP蛋白,胃癌组织中PAP呈阳性表达。从2/4胃癌患者PBMCs中诱导出的PAP多肽特异性CTLs可特异性杀伤HLA-A24+/PAP+的胃癌细胞MKN-45,CTLs的细胞毒活性依赖于CD8+T淋巴细胞。结论PAP有可能成为胃癌特异性免疫治疗的新靶点。

Expression of Prostatic Acid Phosphatase in Gastric Cancer and In Vitro Induction of Anti-gastric Cancer Immunity

Objective To determine the expression level of prostatic acid phosphatase(PAP) in gastric cancer and explore the possibility of PAP as a novel target for immunotherapy of gastric cancer. Methods Determine the expression of PAP mRNA and PAP protein in gastric cancer cell lines by RT-PCR and Western blot respectively, and the expression of PAP protein in gastric cancer tissue by immunohistochemical method. The PBMCs of patients with gastric cancer were stimulated with a PAP epitope peptide in vitro. The PAP-specific IFN-γ was measured by ELISA. The cytotoxicity of CTLs were examined by 51Cr release assay. Results PAP mRNA was expressed in MKN-7, MKN-28 and MKN-45 cell lines, and PAP protein in MKN-28 and MKN-45 cell lines. The expression of PAP was observed in gastric cancer tissue. The PAP-specific CTLs were induced from PBMCs of 2 of 4 patients, which showed CD8+ T lymphocyte-dependent specific killing effect on PAP+ / HLA-A24+ gastric cancer MKN-45 cells. Conclusion PAP might be a novel target for immunotherapy of gastric cancer.