While most human papillomavirus (HPV) infections are short-lived, a subset become chronic and can progress to malignancy, with much greater frequency in HIV infected individuals. Only a dozen 'high risk'HPV types cause cancer but HPV16 alone is responsible for >90% of anal cancer, head and neck cancer and 50% of cervical cancer. Further, 'low risk'HPV types produce considerable morbidity for HIV+ patients. Unfortunately, neither licensed HPV vaccine is effective for treatment of existing infections, and persistent HPV infection and disease remain very prevalent and problematic. HIV+ patients exhibit more chronic and progressive HPV infections than healthy individuals despite HAART, and are at significantly elevated risk for HPV-associated cancers. Poor outcomes of HPV infection are associated with declining CD4 T cell immunity in HIV+ patients. Current non-specific wart treatments frequently fail. Therefore our objective is to develop a therapeutic vaccine to treat chronic HPV infections in the context of HIV despite reduced CD4 T cell help. Recently a laboratory mouse papillomavirus (MusPV) was discovered and sequenced. Published studies suggest that MusPV infection persists in immunodeficient mice but is cleared by 8 weeks in immune competent mice, a situation that closely parallels HPV disease in patients with compromised CD4 T cell immunity versus healthy individuals. We therefore hypothesize that compromised CD4 T cell immunity in mice will permit chronic MusPV infection, and we propose to determine the relationship between persistence of MusPV infection and CD4 T cell immunity. We will explore the impact of CD4 T cell depletion on the development of chronic MusPV infection and papillomas. Several studies indicate that immunization via in vivo electroporation will improve DNA vaccine delivery and efficacy. Furthermore, fusion of the E6 and E7 viral oncoproteins to a heat shock protein, calreticulin (CRT), profoundly enhances the induction of antigen-specific CD8 T cell dependent cellular immunity, even in CD4 T cell-depleted animals. Vaccination of mice with a DNA expressing CRT fused to HPV16 E6, E7 and capsid protein L2 (pNGVL4a-CRTE6E7L2, (PVX01)) induces both antitumor immunity and L2-specific neutralizing antibodies. We hypothesize that vaccination of CD4 T cell-depleted mice with a MusPV version of PVX01 DNA via in vivo electroporation will eliminate chronic papillomavirus disease and elicit protective immunity. Thus, here we propose to characterize the immune response generated by in vivo electroporation of the MusPV version of PVX01 DNA vaccine, including protection from viral challenge, and its therapeutic effect against chronic MusPV infection in CD4 T cell-depleted mice. An effective treatment for HPV disease in HIV+ patients, and the ability to protect them from diverse HPV infections, remains an important unmet medical need. Successful implementation of the current proposal will serve as an important foundation for future transition of the PVX01 DNA vaccine delivered by electroporation to clinical trials in patients with HPV16+ neoplasia and HIV co-infection.
Persistent human papillomavirus (HPV) infections are associated with considerable morbidity and cancer mortality worldwide, and are particularly problematic in patients with HIV. High risk HPV has been identified as the causative agent for 5% of all cancers worldwide, including cervical and other anogenital cancers and a subset of head and neck cancers that afflict HIV+ patients at higher rates. HPV infection and HPV-associated disease of the oral and anogenital sites are highly prevalent and commercial HPV vaccines do not impact pre- existing HPV infection. Thus, the overall objective of our proposal is to develop a vaccine that is effective even in HIV+ patients for the treatment of chronic HPV infections and disease.