Ma Ying, Yang Andrew, Peng Shiwen, Qiu Jin, Farmer Emily, Hung Chien-Fu, Wu T-C
Department of Gynecology and Obstetrics, Zhujiang Hospital of Southern Medical University, Guangzhou, Guangdong Province, China; Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD, United States.
Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD, United States.
Vaccine. 2017 Jul 5;35(31):3850-3858. doi: 10.1016/j.vaccine.2017.05.081. Epub 2017 Jun 7.
Human papillomavirus (HPV) has been identified as the primary etiologic factor of cervical cancer, and subsets of anogenital and oropharyngeal cancers. HPV18 is the second most prevalent high-risk HPV type after HPV16. Furthermore, HPV18 is responsible for approximately 12% of cervical squamous cell carcinoma and 37% of cervical adenocarcinoma cases worldwide. In this study, we aimed to characterize the HPV18-E6-specific epitope and establish an HPV18 animal tumor model to evaluate the E6-specific immune response induced by our DNA vaccine. We vaccinated naïve C57BL/6 mice with a prototype DNA vaccine, pcDNA3-HPV18-E6, via intramuscular injection followed by electroporation, and analyzed the E6-specific CD8+ T cell responses by flow cytometry using a reported T cell epitope. We then characterized the MHC restriction element for the characterized HPV18-E6 epitope. Additionally, we generated an HPV18-E6-expressing tumor cell line to study the antitumor effect mediated by E6-specific immunity. We observed a robust HPV18-E6aa67-75 peptide-specific CD8+ T cell response after vaccination with pcDNA3-HPV18-E6. Further characterization demonstrated that this epitope was mainly restricted by H-2K, but was also weakly presented by HLA-A0201, as previously reported. We observed that vaccination with pcDNA3-HPV18-E6 significantly inhibited the growth of HPV18-E6-expressing tumor cells, TC-1/HPV18-E6, in mice. An antibody depletion study demonstrated that both CD4+ and CD8+ T cells are necessary for the observed antitumor immunity. The characterization of HPV18-E6-specific T cell responses and the establishment of HPV18-E6-expressing tumor cell line provide infrastructures for further development of HPV18-E6 targeted immunotherapy.
人乳头瘤病毒（HPV）已被确认为宫颈癌以及一部分肛门生殖器癌和口咽癌的主要病因。HPV18是仅次于HPV16的第二大常见高危型HPV。此外，全球约12%的宫颈鳞状细胞癌病例和37%的宫颈腺癌病例由HPV18引起。在本研究中，我们旨在鉴定HPV18-E6特异性表位，并建立HPV18动物肿瘤模型，以评估我们的DNA疫苗诱导的E6特异性免疫反应。我们通过肌肉注射随后进行电穿孔，用原型DNA疫苗pcDNA3-HPV18-E6对未经免疫的C57BL/6小鼠进行接种，并使用已报道的T细胞表位通过流式细胞术分析E6特异性CD8+T细胞反应。然后，我们鉴定了所鉴定的HPV18-E6表位的MHC限制元件。此外，我们构建了一个表达HPV18-E6的肿瘤细胞系，以研究E6特异性免疫介导的抗肿瘤作用。在用pcDNA3-HPV18-E6接种后，我们观察到了强烈的HPV18-E6aa67-75肽特异性CD8+T细胞反应。进一步的鉴定表明，如先前报道的那样，该表位主要受H-2K限制，但也可由HLA-A0201弱呈递。我们观察到，用pcDNA3-HPV18-E6接种可显著抑制小鼠体内表达HPV18-E6的肿瘤细胞TC-1/HPV18-E6的生长。一项抗体清除研究表明，CD4+和CD8+T细胞对于观察到的抗肿瘤免疫都是必需的。HPV18-E6特异性T细胞反应的鉴定以及表达HPV18-E6的肿瘤细胞系的建立为HPV18-E6靶向免疫疗法的进一步开发提供了基础。
