RhCMV serostatus and vaccine adjuvant impact immunogenicity of RhCMV/SIV vaccines.

Journal Article (Journal Article)

Rhesus cytomegalovirus (RhCMV) strain 68-1-vectored simian immunodeficiency virus (RhCMV/SIV) vaccines are associated with complete clearance of pathogenic SIV challenge virus, non-canonical major histocompatibility complex restriction, and absent antibody responses in recipients previously infected with wild-type RhCMV. This report presents the first investigation of RhCMV/SIV vaccines in RhCMV-seronegative macaques lacking anti-vector immunity. Fifty percent of rhesus macaques (RM) vaccinated with a combined RhCMV-Gag, -Env, and -Retanef (RTN) vaccine controlled pathogenic SIV challenge despite high peak viremia. However, kinetics of viral load control by vaccinated RM were considerably delayed compared to previous reports. Impact of a TLR5 agonist (flagellin; FliC) on vaccine efficacy and immunogenicity was also examined. An altered vaccine regimen containing an SIV Gag-FliC fusion antigen instead of Gag was significantly less immunogenic and resulted in reduced protection. Notably, RhCMV-Gag and RhCMV-Env vaccines elicited anti-Gag and anti-Env antibodies in RhCMV-seronegative RM, an unexpected contrast to vaccination of RhCMV-seropositive RM. These findings confirm that RhCMV-vectored SIV vaccines significantly protect against SIV pathogenesis. However, pre-existing vector immunity and a pro-inflammatory vaccine adjuvant may influence RhCMV/SIV vaccine immunogenicity and efficacy. Future investigation of the impact of pre-existing anti-vector immune responses on protective immunity conferred by this vaccine platform is warranted.

Full Text

Duke Authors

Cited Authors

  • Chang, WLW; Deere, JD; Kieu, HT; Castillo, LD; Machmach, K; Shen, X; Tomaras, GD; Shacklett, BL; Barry, PA; Hartigan-O'Connor, DJ; Sparger, EE

Published Date

  • August 20, 2020

Published In

Volume / Issue

  • 10 / 1

Start / End Page

  • 14056 -

PubMed ID

  • 32820216

Pubmed Central ID

  • PMC7441386

Electronic International Standard Serial Number (EISSN)

  • 2045-2322

Digital Object Identifier (DOI)

  • 10.1038/s41598-020-71075-x


  • eng

Conference Location

  • England