Phase I Study of a Herpes Simplex Virus Type 2 (HSV-2) DNA Vaccine Administered to Healthy, HSV-2-Seronegative Adults by a Needle-Free Injection System

Abstract

We conducted a double-blind, vehicle-controlled, dose escalation safety and immunogenicity trial of a candidate herpes simplex virus type 2 (HSV-2) surface glycoprotein D2 (gD2) DNA vaccine administered by use of a needle-free device. Sixty-two healthy adults were randomized using a 4:1 vaccine-to-placebo ratio. Half of the participants were HSV-1 seronegative, and all were HSV-2 seronegative. Vaccine doses included 100 g, 300 g, 1,000 g or 3,000 g of a plasmid expressing the gD2 protein. Subjects received vaccine at 0, 4, 8, and 24 weeks. Some subjects received an additional 1,000-g boost at 52 weeks. We found that the vaccine was safe and well tolerated, with most adverse events being local site reactions. No dose-limiting toxicities were observed. gD2-specific cytotoxic T-lymphocyte and lymphoproliferation responses were detected 2 weeks after the third vaccine injection in one of four HSV-1-seronegative, HSV-2-seronegative participants who received 3,000 g of vaccine. A DNA-based vaccination strategy against HSV-2 appears to be safe and may generate a vaccine-specific cellular immune response, but high vaccine doses are likely needed to elicit an immune response in most vaccinees.Herpes simplex virus type 2 (HSV-2) infection is one of the most prevalent sexually transmitted infections worldwide and is a major cause of genital ulcer disease in developed and developing countries (Ahmed et al. 2003, Chen et al. 2000, Mertz et al. 1998, Fleming et al. 1997, Xu et al. 2006. In addition, a growing body of literature suggests that HSV-2 increases the risk of human immunodeficiency virus type 1 (HIV-1) acquisition and transmission (5, 7). HSV-2 also causes neonatal herpes, which is a rare but serious condition that often results in permanent neurodevelopmental sequelae (14). Development of an HSV vaccine is a high priority.Two HSV-2 subunit vaccines have completed phase III trials and provided insight into the immunology of HSV infection. The first contained two major HSV-2 surface glycoproteins, glycoproteins D and B (gB and gD), with an adjuvant, MF59, previously shown to elicit a Th2-type response (31). No protection against HSV-2 acquisition or genital herpes disease was demonstrated, despite elicitation of high HSV-2-specific neutralizing antibody titers (6). The second vaccine contained a truncated form of gD with another adjuvant, aluminum hydroxide plus 3-O-deacylated monophosphoryl lipid A (alum-MPL), previously shown to elicit a Th1-type response (24, 31). This candidate vaccine elicited partial protection against genital herpes disease in women who were seronegative for HSV-1 and -2. The difference in efficacy between these subunit vaccines was attributed to the adjuvants (32). Animal models also suggest that cellular immunity is important in defending against HSV-2 infection (22,23). These data highlight the likelihood that a robust cellular immune response in addition to neutralizing antibodies is critical in protection against HSV-2 infection.DNA vaccination is an attractive approach toward HSV vaccin...

Type-Specific Identification of Anogenital Herpes Simplex Virus Infections by Use of a Commercially Available Nucleic Acid Amplification Test

“…Type specificity is determined based on melting curves. Although the assay is not commercially available, it is considered to be a highly sensitive detection method and has been utilized to describe the pathogenesis of HSV and the association of HSV with HIV-1 infection and to measure clinical outcomes for an HSV vaccine trial (1,4,15). The assay can detect mixed infections with up to a 3-log-unit difference in DNA copy numbers and is estimated to be 3 to 5 times more sensitive than culture performed in the same laboratory (6,16).…”

Nucleofection of DCs to Generate Multivirus-specific T Cells for Prevention or Treatment of Viral Infections in the Immunocompromised Host

“…32,33 Further, plasmids have a proven track record of safety in vivo and have been used in both viral and tumor vaccination trials. [34][35][36][37] On a practical level, clinical grade DNA can be rapidly and costeffectively produced in large quantities and is stable for longterm storage. 38 Our plasmids encoded viral antigens derived from CMV (pp65), Adv (Hexon and Penton), BK (Large T), and EBV (LMP2 and BZLF1), and we based this choice on the encouraging clinical results of our own and other groups showing that T cells directed against AdvHexon and Penton, and CMVpp65 are effective and protective in vivo.…”

Stabilization of Plasmid DNA and Lipid-Based Therapeutics as Dehydrated Formulations

“…Briefly, to date, manufacturing processes (i.e., upstream, fermentation, and downstream processing steps; for in-depth discussion, the reader is referred to articles that offer an extensive and up-to-date review of the processes [136,[161][162][163]) involved in the production of cGMP-grade plasmid DNA (drug substance) for human clinical trials have been designed in order to be cost-effective, efficient, and capable of producing largescale quantities of SC pharmaceutical-grade plasmid DNA (e.g., ≥ 200 mg for pilot and early clinical trials or gram-to-kilogram quantities at industrial scale [122,140,[164][165][166][167][168]). Accordingly, these higher capacities allow the preparation of DNA gene therapy or DNA vaccine formulations for clinical trials at the higher concentrations required (≥ 0.5 mg/mL) [30,[169][170][171].…”