免疫增强型胰腺癌MUC1-VNTR—C144DNA疫苗的构建

The construction of new immunopotentiating MUC1-VNTR-C144 DNA vaccine for pancreatic cancer

目的构建免疫增强型胰腺癌MUC1-VNTR—C144DNA疫苗。方法在pcDNA3．1-VNTR／Myc—his（＋）A质粒靶基因之后插入乙型肝炎病毒核心抗原C144基因，构建MUC1-VNTR—C144DNA疫苗。45只C57BL／6小鼠随机分3组，VC组接种pcDNA3．1-VNTR—C144／Myc—his（＋）A质粒，V组单纯接种pcDNA3．1-VNTR／Myc—his（＋）A质粒，C组单纯接种pcDNA3．1-C144／Myc—his（＋）A质粒。4周后加强免疫1次。结果VC组小鼠脾细胞毒性T淋巴细胞（CTL）的特异性杀伤率（46．7±8．2）％显著高于V组（34．8±3．1）％和C组（12．9±1．2）％（E／T=80／1，P〈0．01）。而CTL对未经VNTR合成肽孵育的靶细胞EL4-VNTR^-杀伤率较低（P〈0．01），Vu3C6可抑制CTL对经VNTR合成肽孵育的靶细胞EIA—VNTR’的杀伤活性（P〈0．01），表明具有VC组诱生的CTL应答依然保持VNTR特异性。VC组小鼠血清抗VNTR抗体等效浓度（2810．2±308．3）mg／L高于V组（2323．5±238．3）mg／L和C组（2130．9±138．5）mg／L，差异有统计学意义（P〈0．01）。结论增强型胰腺癌MUC1-VNTR—C144DNA疫苗所诱生的VNTR特异的CTL应答和抗体应答显著增强。

Objective To construct new MUCI-VNTR-C144 DNA vaccine for pancreatic cancer and study both CTL responses and antibody responses specific to VNTR enhanced by the C144 gene. Methods DNA encoding the 144 amino acids of the N-terminus of HBV core gene was cloned and then inserted into the recombinant plasmid pcDNA3.1-VNTR/Myc-his（ ＋ ） A. C57BL/6 mice were randomly immunized intramusscularly into anterior tibialis muscle with 100 μg plasmid DNA encoding VNTR （V group,n = 15） or VNTR/C144 （VC group,n = 15）. Mice injected with the plasmid pcDNA3.1-C144/Myc-his （ ＋ ） A vector （ C group, n = 15 ） were used as controls. Four weeks later, all mice were injected a- gain with the same solution as before. Two weeks after the last immunization, spleen cells were obtained and analyzed for cytotoxic activity 6 days after in vitro stimulation by the synthesized VNTR polypeptide （Calcein AM assay）. Blood was collected for the ELISA assay of anti-VNTR antibodies. Results The specific CTL killing rate against VNTR pelypeptide induced in the VC group （46.7 ± 8.2 ） % was signifi- cantly higher than in the V group （34.8 ± 3.1 ） % and the C group （ 12.9 ± 1.2） % （ P 〈 0.01 ） ,indicating the Cldd gene enhances the CTL response induced by the vaccine. However, CTL lysed much more VNTR positive EIA than VNTR negative EIA （P 〈 0.01 ）, while the anti-VNTR antibody VU 3C6 significantly restrained such activity （P 〈0.01 ）, which indicated the CTL response was specific to VNTR. The equivalent concentration of specific antibody against VNTR in the VC group （2810.2 ±308.3 ） mg/L was signif- icantly higher than the V group （2323.5 ±238.3） mg/L and the C group （2130.9 ± 138.5 ） mg/L （P 〈 0.01 ） ,which implied that the Cld4 gene could enhance the antibody response induced by the vaccine.Conclusion The VNTR specific CTL response and antibody response induced in mice immunized with new MUC1-VNTR-C144 DNA vaccine for pancreatic cancer can be enhanced significantly by the C144 gene.