Persistent infection with high-risk genotypes of human papillomavirus (HPV) is the leading cause of cervical cancer. The HPV oncoprotein E7 is constitutively expressed in cervical cancer and considered as an essential target for tumor-specific immunity. The goal of this study was to develop a candidate therapeutic vaccine based on the mutated E7 protein that had possibly reduced transformation capacity while was able to elicit a robust immune response. Therefore, the mutant type of HPV 16 E7 (E7GRG) protein was recombinantly expressed in E. coli. The protein was then purified and formulated with 2’-3’cGAMP CDN and/or CpG-C ODN adjuvants and subcutaneously injected to female C57BL/6 mice. To evaluate the immunogenic response, lymphocyte proliferation, secretion levels of IFN-γ and IL-4 cytokines, granzyme B level, and total IgG and subclasses of IgG antibody were measured. The anti-tumor activity was evaluated in tumor-harboring C57BL/6 mice. The highest rate of cell proliferation, IFN-γ and granzyme B levels, and amount of IgG antibody were found in mice group that were injected by E7GRG + 2′-3′cGAMP + CpG-C. Therapeutic immunization with E7GRG + 2′-3′cGAMP + CpG-C also significantly suppressed TC-1 tumor growth in mice. In conclusion, the results demonstrated that E7GRG + 2′-3′cGAMP + CpG-C induced strong cell-mediated and humoral immune responses that resulted in inhibition of tumor in mouse model.

中文翻译：

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2'3'-cGAMP STING激活剂和CpG-C佐剂与HPV 16 E7蛋白突变形式的共同给药导致小鼠模型中的肿瘤生长抑制

高危基因型人乳头瘤病毒（HPV）的持续感染是宫颈癌的主要原因。HPV癌蛋白E7在宫颈癌中组成性表达，被认为是肿瘤特异性免疫的重要靶标。这项研究的目的是开发一种基于突变的E7蛋白的候选治疗疫苗，该疫苗可能降低了转化能力，同时能够引发强大的免疫反应。因此，HPV 16 E7（E7GRG）蛋白的突变型在大肠杆菌中重组表达。然后纯化该蛋白，并用2'-3'cGAMP CDN和/或CpG-C ODN佐剂配制，并皮下注射给雌性C57BL / 6小鼠。为了评估免疫原性反应，淋巴细胞增殖，IFN-γ和IL-4细胞因子的分泌水平，颗粒酶B水平，测定总IgG和IgG抗体的亚类。在具有肿瘤的C57BL / 6小鼠中评估了抗肿瘤活性。E7GRG + 2'-3'cGAMP + CpG-C注射的小鼠组细胞增殖率最高，IFN-γ和颗粒酶B水平最高，IgG抗体含量最高。用E7GRG + 2'-3'cGAMP + CpG-C进行的治疗性免疫还显着抑制了TC-1肿瘤在小鼠中的生长。总之，结果表明，E7GRG + 2'-3'cGAMP + CpG-C诱导了强烈的细胞介导的体液免疫反应，从而抑制了小鼠模型的肿瘤。E7GRG + 2'-3'cGAMP + CpG-C注射后，小鼠组中发现了IgG抗体的量。用E7GRG + 2'-3'cGAMP + CpG-C进行的治疗性免疫还显着抑制了TC-1肿瘤在小鼠中的生长。总之，结果表明，E7GRG + 2'-3'cGAMP + CpG-C诱导了强烈的细胞介导的体液免疫反应，从而抑制了小鼠模型的肿瘤。E7GRG + 2'-3'cGAMP + CpG-C注射后，小鼠组中发现了IgG抗体的量。用E7GRG + 2'-3'cGAMP + CpG-C进行的治疗性免疫还显着抑制了TC-1肿瘤在小鼠中的生长。总之，结果表明，E7GRG + 2'-3'cGAMP + CpG-C诱导了强烈的细胞介导的体液免疫反应，从而抑制了小鼠模型的肿瘤。