Abstract 2364: Spontaneous and vaccine-induced clearance of Mus Musculus Papillomavirus1 (MusPV1) infection

Abstract

Abstract Human papilloma virus (HPV) high risk (hr) types cause several cancers, including cervical, vaginal, penile, and oropharyngeal, whereas low risk types cause benign diseases such as skin warts, anogenital warts and recurrent respiratory papillomatosis. Although hrHPV infection is one of the most common sexually transmitted diseases most infections remain asymptomatic and are cleared while a sub-population develops persistent HPV-related pathologies including cancer. Further, immune-compromised populations, notably organ transplant and HIV-positive patients, are particularly vulnerable to HPV-related pathologies. Here, we describe the first establishment of mouse papillomavirus-1 (MusPV1) disease in outbred and immune competent SKH1-Elite mice (Crl:SKH1-Hrhr). Challenge of SKH1 mice with MusPV1 resulted in three clinical outcomes: 1) persistent (>2 months) papillomas (∼15%), 2) transient papillomas that spontaneously regress typically within 2 months (∼10%), 3) no visible papillomas and viral clearance (∼75%). SKH1 mice with persisitent papillomas were treated using a potentially preventive and therapeutic DNA vaccine composed of human calreticulin (hCRT) linked to MusPV1 early proteins, mE6 and mE7 and the late protein mL2 (hCRTmE6/mE7/mL2). Three intramuscular DNA vaccinations (15 μg in PBS) via in vivo electroporation were administered weekly and immune responses were measured, including mE6/mE7/mL2 serum antibody response and T-cell epitope mapping studies. Previously persistent papillomas disappeared within 2 months after final vaccination. Clearance of MusPV1 was confirmed by loss of mE6/mE7 transcript staining using RNA-CISH on formalin-fixed, paraffin-embedded tail sections. Vaccination induced a strong mE6 and mE7 CD8+ T cell response in all mice. Interestingly, mL2 antibody responses were faster and stronger in asymptomatic challenged mice and in those that spontaneously cleared their papillomas after challenge as compared to mice with persistent papillomas. In sum, MusPV1 challenge of outbred, immune-competent SKH1 mice represents a promising model to further study potential immunotherapies for HPV-related disease and the relationship between spontaneous clearance of papillomavirus and host genetics. Citation Format: Rosie T. Jiang, Joshua W. Wang, Shiwen Peng, Chien-Fu Hung, Richard B.S Roden. Spontaneous and vaccine-induced clearance of Mus Musculus Papillomavirus1 (MusPV1) infection. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2364.