Cervical cancer is caused by persistent high-risk human papillomavirus (HR-HPV) infection and represents the second most frequent gynecological malignancy in the world. The HPV-16 type accounts for up to 55% of all cervical cancers. The HPV-16 oncoproteins E6 and E7 are necessary for induction and maintenance of malignant transformation and represent tumor-specific antigens for targeted cytotoxic T lymphocyte–mediated immunotherapy. Therapeutic cancer vaccines have become a challenging area of oncology research in recent decades. Among current cancer immunotherapy strategies, virus-like particle (VLP)–based vaccines have emerged as a potent and safe approach. We generated a vaccine (VLP-E7) incorporating a long C-terminal fragment of HPV-16 E7 protein into the infectious bursal disease virus VLP and tested its therapeutic potential in HLA-A2 humanized transgenic mice grafted with TC1/A2 tumor cells. We performed a series of tumor challenge experiments demonstrating a strong immune response against already-formed tumors (complete eradication). Remarkably, therapeutic efficacy was obtained with a single dose without adjuvant and against two injections of tumor cells, indicating a potent and long-lasting immune response.

This work was supported in part by grants PIE/473/2009 and PIE/506/2008 from Instituto Madrileño de Desarrollo, 25/2008 from Comunidad Autónoma de Madrid, CIT-010000-2008-18 from Ministerio de Educación, FIT-010000-2007-68 from Ministerio de Industria, Turismo y Comercio, and CIT-010000-2007-34 from Ministerio de Ciencia e Innovación (PROFIT). Additional support was provided by Consorci Parc de Recerca Biomédica de Barcelona.