Project 2

The increased rates of HPV-associated malignancy in HIV+ patients and organ transplant recipients, as well as a wealth of preclinical studies, suggest the importance of cellular immunity in controlling infection. In contrast, current HPV vaccines induce neutralizing antibodies that are central to preventive vaccination, but they lack therapeutic activity. To accelerate the impact of HPV vaccination even in HIV+ patients, here our goal is to develop a combined therapeutic and preventive approach to eradicate established infection and/or HPV-associated precancerous lesions by inducing cell-mediated immunity, as well as to elicit broadly protective humoral immunity to prevent new HPV infections. We have previously developed a candidate therapeutic and preventive DNA vaccine, pNGVL4aCRTE6E7L2 (CRTE6E7L2), which encodes calreticulin linked to HPV16 E6, E7, and L2 proteins. The CRTE6E7L2 DNA vaccine is particularly promising for use in HIV+ patients to treat HPV16-associated lesions as well as to generate a pan-HPV protective effect against new or re-infection for several reasons. First, DNA vaccines are safe, even for immunocompromised individuals, in that they do not contain live pathogen but still elicit cell-mediated and/or humoral immune responses. Second, we recently shown that electroporation with a DNA encoding calreticulin linked to HPV tumor antigens still elicits a potent HPV-specific CD8+ T cell response even in CD4-depleted animals and that these responses can control HPV+ tumor. This remarkable finding suggests that CRTE6E7L2 may be active in HIV+ patients, even those with low-level CD4+ T cell counts, a group in which HPV-disease is particularly difficult to treat as conventional ablative treatment of CIN2/3 is associated with high rates of recurrence. Finally, the broadly protective effects of L2-specific neutralizing antibody have the potential to prevent new infections with the unusual HPV types and high rates of multi-type HPV infections seen in the HIV+ population. Due to the prevalence and diversity of HPV types and the lack of antiviral agents for HPV, development of broad-spectrum prophylactic vaccines against all 14 high-risk HPV is an attractive strategy in the prevention of the HPV-associated cancer in HIV+ patients. Nevertheless, our focus remains on HPV16 as it is the most common type in cervical cancer and is dominant in other anogenital and head and neck malignancies.

Although DNA vaccines are relatively safe and well suited for multiple administrations, they generally exhibit suboptimal immunogenicity when administered by conventional intramuscular (i.m.) needle injection, likely reflect inefficient host cell transduction. In order to overcome this obstacle, we will use in vivo electroporation, which involves DNA plasmid administration to the target tissue followed by brief electrical pulses at the administration site to transiently increase cell membrane permeability. Consequently, this allows the cells to have increased uptake of and expression from the DNA plasmid. Our overall goal is to use the Ichor TriGrid™ Delivery System Electroporation Device, which has been used safely in multiple clinical trials, for i.m. administration of the CRTE6E7L2 DNA vaccine at escalating doses in both HIV– and HIV+ patients with HPV16-associated high-grade cervical intraepithelial neoplasia grades 2 and 3, and to examine the safety, virologic, and disease outcomes.

Aim 1: To evaluate the safety and toxicity of CRTE6E7L2 administered via electroporation in HIV– and HIV+ patients with HPV16+ CIN2/3.

Aim 2: To characterize the HPV16 E6/E7-specific cell-mediated and humoral immune responses in HIV– and HIV+ patients with HPV16+ CIN2/3 vaccinated with CRTE6E7L2 via electroporation.

Aim 3: To characterize L2-specific humoral immune responses in HIV– and HIV+ patients with HPV16-associated CIN2/3 upon vaccination with CRTE6E7L2 DNA vaccine via electroporation.

Aim 4: To determine the HPV viral load and histopathological changes in the lesion and its microenvironment in HIV– and HIV+ patients with HPV16-associated CIN2/3 upon treatment with CRTE6E7L2 DNA vaccine via electroporation.

Investigators