HSV-2 vaccine: current status and insight into factors for developing an efficient vaccine

Abstract

Herpes simplex virus type 2 (HSV-2), a globally sexually transmitted virus, and also one of the main causes of genital ulcer diseases, increases susceptibility to HIV-1. Effective vaccines to prevent HSV-2 infection are not yet available, but are currently being developed. To facilitate this process, the latest progress in development of these vaccines is reviewed in this paper. A summary of the most promising HSV-2 vaccines tested in animals in the last five years is presented, including the main factors, and new ideas for developing an effective vaccine from animal experiments and human clinical trials. Experimental results indicate that future HSV-2 vaccines may depend on a strategy that targets mucosal immunity. Furthermore, estradiol, which increases the effectiveness of vaccines, may be considered as an adjuvant. Therefore, this review is expected to provide possible strategies for development of future HSV-2 vaccines.

Figure 1

Illustration of pathogenesis and immune responses of HSV-2 in vaccine development. (A) HSV-2 glycoproteins, especially gB and gD, are widely used to develop subunit vaccine and peptide vaccine. DNA has also been frequently used for vaccine development; (B) The transcription and translation of the genes lead to HSV-2 shedding and recurrent episodes; (C) The ability of gD to induce specific antibody is the strongest. The combination of gD with HVEM triggers immediate innate immune response, which leads to subsequent adaptive immune response.

Figure 2

Factors of developing an effective vaccine. (A) The size of the circle represents the importance of the factor; (B) The progress in HSV-2 pathogenesis will promote the development of vaccine formulation; (C) The progress in HSV-2 immune response will promote the development of vaccine formulation; (D) The progress in HSV-2 pathogenesis will promote the development of immunization route; (E) The progress in HSV-2 immune response will promote the development of immunization route.