Immunogenicity and protective efficacy of a DNA vaccine against Venezuelan equine encephalitis virus aerosol challenge in nonhuman primates

A study to evaluate the immunogenicity and protective efficacy of a Venezuelan equine encephalitis virus (VEEV) DNA vaccine in an aerosol model of nonhuman primate infection was performed Cynomolgus macaques vaccinated with a plasmid expressing the 26S structural genes of VEEV subtype IAB by particle-mediated epidermal delivery (PMED) developed virus-neutralizing antibodies No serum viremia was detected in two out of three macaques vaccinated with the VEEV DNA after aerosol challenge with homologous virus while one displayed a low viremia on a single day postchallenge In contrast all three macaques vaccinated with empty vector DNA developed a high viremia that persisted for at least 3 days after challenge In addition macaques vaccinated with the VEEV DNA had reduced febrile reactions lymphopenia and clinical signs of disease postchallenge as compared to negative control macaques Therefore although the sample size was small in this pilot study these results indicate that a VEEV DNA vaccine administered by PMED can at least partially protect nonhuman primates against an aerosol VEEV challenge (C) 2010 Elsevier Ltd All rights reserved