Project 5

Vaccination with Sig/E7(detox)/HSP70 DNA to Treat Patients with HPV-Associated High Grade Squamous Intraepithelial Lesions with or without HIV

Description

The goal of this project is to evaluate a therapeutic, antigen-specific vaccine strategy targeted at the E7 antigen of human papillomavirus (HPV) type 16, the most common HPV type found in both cervical cancer and its precursor lesion, cervical intraepithelial neoplasia (CIN). Cervical cancer is a sexually transmitted disease caused by infection with a high risk strain of HPV. The HPV E7 gene product is consistently expressed in CIN and in cervical cancers, and is functionally required to maintain the transformed state. HPV infection and subsequent development of squamous neoplasia is more common in patients with deficient cell-mediated immunity. In patients infected with human immunodeficiency virus (HIV), the risk of HPV infection is twice normal even in women with normal CD4 counts. We have developed a DNA vaccine strategy which targets a detox form of HPV16 E7 (E7(detox)) to the MHC class I processing pathway. In an E7-expressing preclinical mouse tumor model, gene gun vaccination with E7(detox)/HSP70 DNA elicits a potent E7-specific immune response which is completely independent of the CD4 arm, and furthermore results in significant antitumor effect. We then added signal peptide (Sig) to this construct and demonstrated that intramuscular (IM) injection with pNGVL4a-Sig/E7(detox)/HSP70 DNA generated E7-specific CD8+ responses comparable to those generated by gene gun immunization with E7(detox)/HSP70. We have secured RAID support for making GMP grade pNGVL4a-Sig/E7(detox)/HSP70 DNA for evaluating its safety and therapeutic potential in HIV-positive and -negative patients with HPV16+ CIN3. Our specific aims are: 1) to evaluate safety and toxicity of IM immunization with pNGVL4a-Sig/E7(detox)/HSP70 DNA in HIV+ and - patients with HPV16-associated CIN3 lesions, 2) to identify any clinical responses to vaccination using HPV viral load, pathologic changes, and colposcopic evaluation, 3) to identify and characterize E7-specific humoral and T cell-mediated immune responses before and after vaccination and correlate these measures with clinical responses, and 4) to characterize infiltrating immune cells and cytokine profiles, and to correlate these data with HPV viral load and histopathology before and after vaccination.