Human papillomavirus (HPV), particularly type 16, has been identified as the major etiologic agent of cervical cancer.
We aim both to prevent HPV infection of the genital mucosa and to treat established or breakthrough infection by exploiting the properties of HPV virus-like particles (VLPs). Papillomavirus VLPs are highly antigenic and induce high titer serum neutralizing antibodies that protect animals from experimental infection. However, immunization with VLPs is not therapeutic. Since the HPV capsid representing a promising vehicle for gene delivery to cells that express the HPV receptor (alpha6 integrin), such as dendritic cells, we propose to use HPV particles to deliver a therapeutic HPV-16 E7-specific DNA-based vaccine. E7 is expressed in all HPV-containing cervical cancers and their precursor lesions, and therefore represents a good immunological target for the treatment of HPV-induced disease. To enhance immune presentation we fused the sorting signals of the lysosome associated membrane protein (LAMP-1) to E7, thus creating the Sig/E7/LAMP-1 chimera. We demonstrated that vaccination with DNA that expressed Sig/E7/LAMP-1 eliminates E7-transformed syngeneic tumors in mice. To promote efficient delivery of this therapeutic vaccine to professional antigen presenting cells and generate a novel preventive/therapeutic HPV vaccine we plan to incorporate Sig/E7/LAMP-1 plasmid DNA into HPV-16 VLP. As a prelude to clinical study, we will determine the ability of this non-replicative pseudovirion vaccine to generate protective neutralizing antibodies against HPV capsid proteins, to enhance therapeutic DNA vaccine delivery and to treat E7-expressing murine model tumors. Specifically, we propose to do the following: DNA vaccine delivery and to treat E7- expressing murine model tumors. Specifically, we propose to do the following: A.1 Generate and characterize HPV16 {pCMV Sig/E7/LAMP- 1} pseudovirions. A.2 Compare the ability of HPV16 {pCMV Sig/E7/LAMP-1} peusdovirions to induce HPV neutralizing antibody and long-lasting E7-specific cell mediated immune responses with HPV16 VLPs and naked pCMV Sig/E7/LAMP-1 DNA vaccines respectively. A.3 Evaluate the E7-specific anti-tumor effects of HPV16{pCMV Sig/E7/LAMP-1} pseudovirions using E7-expressing murine tumor models and determine the optimal route of administration for HPV16 {pCMV Sig/E7/LAMP-1} pseudovirion vaccination. A.4 Compare several Sig/E7/LAMP-1 containing vaccines including Sig/E7/LAMP-1 vaccinia, naked Sig/E7/LAMP-1 DNA vaccine and HPV16[pCMV Sig/E7/LAMP-1}psudovirions head-to-head for the protection and treatment of established E7-expressing murine tumors and evaluate the potential synergies between different Sig/E7/LAMP-1 vaccines. A.5 Evaluate the mechanisms of the anti-tumor immunity induced by vaccination.
