Vaccination is a proven intervention against human viral diseases; however， success against Herpes Simplex Virus 2 (HSV-2) remains elusive. Most HSV-2 vaccines tested in humans to date contained just one or two immunogens， such as the virion attachment receptor glycoprotein D (gD) and/or the envelope fusion protein， glycoprotein B (gB). At least three factors may have contributed to the failures of subunit-based HSV-2 vaccines. First， immune responses directed against one or two viral antigens may lack sufficient antigenic breadth for efficacy. Second， the antibody responses elicited by these vaccines may have lacked necessary Fc-mediated effector functions. Third， these subunit vaccines may not hav... More
Vaccination is a proven intervention against human viral diseases; however， success against Herpes Simplex Virus 2 (HSV-2) remains elusive. Most HSV-2 vaccines tested in humans to date contained just one or two immunogens， such as the virion attachment receptor glycoprotein D (gD) and/or the envelope fusion protein， glycoprotein B (gB). At least three factors may have contributed to the failures of subunit-based HSV-2 vaccines. First， immune responses directed against one or two viral antigens may lack sufficient antigenic breadth for efficacy. Second， the antibody responses elicited by these vaccines may have lacked necessary Fc-mediated effector functions. Third， these subunit vaccines may not have generated necessary protective cellular immune responses. We hypothesized that a polyvalent combination of HSV-2 antigens expressed from a DNA vaccine with an adjuvant that polarizes immune responses toward a T helper 1 (Th1) phenotype would compose a more effective vaccine. We demonstrate that delivery of DNA expressing full-length HSV-2 glycoprotein immunogens by electroporation with the adjuvant interleukin 12 (IL-12) generates substantially greater protection against a high-dose HSV-2 vaginal challenge than a recombinant gD subunit vaccine adjuvanted with alum and monophosphoryl lipid A (MPL). Our results further show that DNA vaccines targeting optimal combinations of surface glycoproteins provide better protection than gD alone and provide similar survival benefits and disease symptom reductions compared with a potent live attenuated HSV-2 0ΔNLS vaccine， but that mice vaccinated with HSV-2 0ΔNLS clear the virus much faster. Together， our data indicate that adjuvanted multivalent DNA vaccines hold promise for an effective HSV-2 vaccine， but that further improvements may be required.
