人乳头状瘤病毒16型多肽疫苗的制备及体内外效应观察

目的 探讨人乳头状瘤病毒(HPV)16型多肽疫苗的制备,并观察HPV16多肽疫苗的体内外效应.方法 (1)针对抗原加工相关转运子(TAP)设计HPV16 E7蛋白的主要组织相容性复合物Ⅰ类分子(MHC-I)的抗原结合表位,利用生物信息学分析平台筛选出一致性较高、特异性及亲和力较强的HPV16 E7多肽作为研究对象制备HPV16多肽疫苗用于以下研究,本研究共筛选出3段多肽,分别命名为E7Pa、E7Pb、E7Pc.(2)C57BL/6小鼠注射鼠肺上皮细胞株TC-1细胞(为鼠源性的HPV16阳性的肿瘤细胞株)后,采用等额抽取的随机方法分为5组,ETPa+二核苷胞嘧啶(CpG)、E7Pb+CpG、E7Pc+CpG[均为实验组,分别加入终浓度为50μg/ml的E7Pa、E7Pb、E7Pc和终浓度为12 mg/L的刀豆蛋白(ConA)]、CpG(为阳性对照,加入终浓度为12 mg/L 的Con A)和空白对照组(不做任何处理).采用四甲基偶氮唑蓝(MTT)比色法检测各组作用不同时间后小鼠脾T淋巴细胞的体外增殖效应,乳酸脱氢酶(LDH)释放法检测小鼠脾T淋巴细胞在不同效靶比下的体外细胞毒T淋巴细胞(CTL)活性,实时荧光定量RT-PER技术检测小鼠肿瘤组织中γ干扰素(IFN-γ)、白细胞介素2(IL-2)mRNA的表达水平,酶联免疫吸附试验(ELISA)检测小鼠外周血中IFN-γ、IL-2的表达水平,通过定期测量比较各组小鼠接种HPV16多肽疫苗后体内肿瘤体积的变化.结果 (1)本研究筛选出了一致性较高、特异性及亲和力较强的3段HPV16 E7多肽作为研究对象制备HPV16多肽疫苗,分别命名为E7Pa、E7Pb、E7Pc.(2)MTT比色法检测显示,在接种疫苗24、48、72、96 h后,以E7Pa+CpG组的增殖效应最明显,其细胞增殖率分别为(131±32)%、(302±15)%、(552±28)%、(731±24)%,明显高于空白对照组的(72±15)%、(120±57)%、(176±41)%、(288±29)%(P<0.01);E7Pb+CpG、ETPc+CpG、CpG组的细胞增殖率也均明显高于空白对照组(P<0.05);但E7Pb+CpG、E7Pc+CpG、CpG组间比较,差异则无统计学意义(P>0.05).LDH释放法榆测显示,效靶比为100:1时,E7Pa+CpG、E7Pb+CpG、E7Pc+CpG、CpG和空白对照组CTL 活性分别为(85.9±3.0)%、(55.9±2.5)%、(60.2±1.5)%、(41.0±1.7)%和(4.1±1.0)%,E7Pa+CpG组与空白对照组比较,差异有统计学意义(P<0.01);E7Pb+CpG、E7Pc+CpG、CpG组分别与空白对照组比较,差异也有统计学意义(P<0.05);但E7Pb+CpG、E7Pc+CpG、CpG组间比较,差异则无统计学意义(P>0.05).在肿瘤组织及外周血中,小鼠IFN-γ、IL-2的表达水平,E7Pa+CpG组与空白对照组比较,差异均有统计学意义(P<0.01);E7Pb+CpG、E7Pc+CpG和CpG组分别与空白对照组比较,差异也均有统计学意义(P<0.05);但E7Pb+CpG、E7Pc+CpG、CpG组问比较,差异则无统计学意义(P>0.05).小鼠体内的肿瘤体积,各实验组肿瘤生长均明显被抑制,接种后第60大,E7Pa+CpG组与空白对照组比较,差异有统计学意义(P<0.01);E7Pb+CpG、E7Pc+CpG和CpG组分别与空白对照组比较,差异也均有统计学意义(P<0.05);但 E7Pb+CpG、E7Pc+CpG、CpG组间比较,差异则无统计学意义(P>0.05).结论 在动物模型中,针对TAP筛选的HPV16 E7多肽联合CpG制备的HPV16多肽疫苗,可以有效治疗HPV16 E7阳性的肿瘤.

Preparation of human papillomavirus 16 E7 peptide vaccine and its effectiveness in vitro and in vivo

Objective To prepare the human papillomavirus (HPV) 16 peptide vaccine and explore the effect in vitro and in vivo. Methods (1) Prediction of the major histocompatibility complex (MHC) class I restricted T cell epitopes by bioinformatics target at transporter associated with antigen processing (TAP) and named by E7Pa, E7Pb, E7Pc separately. (2)In vivo, the C57BL/6 mice were divided into five groups with same amounts randomly after loading with TC-1 cells (HPV 16 positive tumor cells from C57BL/6 mouse), named as E7Pa + CpG,E7Pb + CpG,E7Pc + CpG (as experiment groups, and added 50 μg/ml E7Pa, E7Pb, E7Pc, respectively), CpG(as positive control group and added Con A with 12 mg/L final concentration) and blank control group (without any treatment). The T cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay at different time points;the lactate dehydrogenase (LDH) delivery method was used to test the cytolytie T lymphocyte (CTL) activity of mouse splenic lymphocyte in different ratio of effector cells and target cells (E:T);the related cytokines in tumor tissue and mouse peripheral blood were evaluated by real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. The tumor volumes were measured to contrast the therapeutic effect in different groups. Results (1) Three peptide named E7Pa, E7Pb, E7Pc were successfully preparated which had high affinity and specificity. (2) After vaccination of 24, 48, 72,96 hours, MTT results shown that the proliferation rate in E7Pa + CpG group were(131±32)%, (302±15)%, (552±28)%, (731±24)% individually, which were much higher than those in blank control [(72± 15) %, (120 ± 57) %, (176 ±41)%, (288±29)% ;P<0.01], and the other groups i. e. E7Pb + CpG,E7Pc +CpG and CpG groups all proliferated much higher than those in blank control group with statistic signification (P<0. 05), but there was no significant difference between groups(P>0.05);the LDH delivery assay showed that when the ratio of E:T was 100:1, the activity of CTL in the E7Pa + CpG group was most powerful than the other groups with statistic signification (P<0. 01). Meanwhile, the ratio of E:T was concentration-dependent. Compared E7Pb + CpG, E7Pc + CpG or CpG groups with blank control group, there were significantly difference(P<0. 05) ,while there was no significant difference between groups(P >0. 05). The mRNA levels of interferon γ (IFN-γ), interleukin-2 (IL-2) in tumor tissue and peripheral blood in E7Pa + CpG group were significantly higher than those in blank control group (P<0. 01), which was the similar results when compared E7Pb + CpG, E7Pc + CpG or CpG groups with control group (P < 0. 05), and without significant difference between groups(P > 0. 05). The tumor volumes were suppressed obviously in all the experiment groups, especially at the 60th days, the volumes in ETPa + CpG group were much smaller than that in blank control group with statistic signification (P < 0. 01),which was the similar results that E7Pb + CpG, E7Pc + CpG or CpG groups had difference than blank control group with statistic signification (P < 0. 05), and without significant difference between groups(P >0. 05). Conclusion The HPV16 E7 peptide target at TAP combination with CpG as a vaccine could treat effectively the HPV16 E7 positive tumor in experiment.