重组表皮生长因子受体噬菌体疫苗的抗肿瘤效果

目的构建重组表皮生长因子受体(EGFR)噬菌体疫苗,并观察其抗肿瘤效果。方法将鸡源EGFR膜外部分的5个基因片段插入T7噬菌体表达系统中,EGFR蛋白以融合蛋白的形式表达在噬菌体的外壳蛋白10B上,从而构建成噬菌体疫苗。Western blot方法检测噬菌体壳蛋白的EGFR表达,ELISA方法检测免疫小鼠血清中抗EGFR抗体。分离免疫小鼠脾细胞,检测淋巴细胞对靶细胞A431的细胞毒作用。C57BL／6J小鼠经过4次免疫,接种Lewis肺癌细胞,记录肿瘤的生长情况,评价疫苗的抗肿瘤效果。结果成功构建5种鸡源EGFR噬菌体疫苗REPV-C1、REPV-C2、REPV-C3、REF-C4和REPV-C5。Western blot结果显示,噬菌体壳蛋白上有EGFR表达。经免疫的小鼠血清中可检测到抗EGFR抗体。免疫后的小鼠脾细胞对EGFR受体高表达的A431细胞具有杀伤作用,效靶比为10:1时,最大杀伤率可达45．74％±7．21％。肿瘤生长曲线显示,免疫后的C57BL／6J小鼠Lewis肺癌生长受到明显抑制。结论重组EGFR噬菌体疫苗具有抗肿瘤效果,利用噬菌体表达技术构建噬菌体疫苗是一种有效的抗肿瘤方法。

Immunotherapeutic effect of recombinant EGFR phage vaccine on tumors

OBJECTIVE: To construct a recombined phage vaccine and to evaluate the efficiency of this phage vaccine against EGFR-positive tumors. METHODS: T7 phage display system was used to display five fragments of the extracellular domain of chicken EGFR. The EGFR was expressed as a fused protein on the surface of the T7 phage 10B capsid protein. The EGFR expression of the phage vaccine was verified by Western-blot analysis. Anti-EGFR antibody was detected by ELISA. Splenic lymphocytes of the immunized mice were separated and used to determine the immunotoxic effect against A431 cells. The phage vaccines were injected into C57 mice 4 times before Lewis lung cancer cells inoculation. Tumor volume was recorded to evaluate the anti-tumor effect of each vaccine. RESULTS: Five phage vaccines inserted with the chicken EGFR gene were successfully constructed. Western blot assay showed that the extracellular domain of chicken EGFR proteins were displayed on the surface of the phage. Specific antibody was induced in the immunized mice, compared with the control group. Splenic lymphocytes of the immunized mice were shown to be immunotoxic against A431 cells. The killing rates of the experimental groups were higher than that of control group (P < 0.001, t-Student test). The highest killing rate was (45.74 +/- 7.21)%. The tumor growth was inhibited in the experimental groups compared with those of control groups (P < 0.05 in C1, C2, C3, C4 groups, P > 0.05 in C5 group). CONCLUSION: Our results demonstrated that recombined EGFR phage vaccines may be used to induce therapeutic anti-tumor immunity against EGFR-positive tumors.