Early antiretroviral therapy limits SIV reservoir establishment to delay or prevent post-treatment viral rebound

Nat Med. 2018 Sep;24(9):1430-1440. doi: 10.1038/s41591-018-0130-7. Epub 2018 Aug 6.


Prophylactic vaccination of rhesus macaques with rhesus cytomegalovirus (RhCMV) vectors expressing simian immunodeficiency virus (SIV) antigens (RhCMV/SIV) elicits immune responses that stringently control highly pathogenic SIV infection, with subsequent apparent clearance of the infection, in ~50% of vaccinees. In contrast, here, we show that therapeutic RhCMV/SIV vaccination of rhesus macaques previously infected with SIV and given continuous combination antiretroviral therapy (cART) beginning 4-9 d post-SIV infection does not mediate measurable SIV reservoir clearance during over 600 d of follow-up on cART relative to RhCMV/control vaccination. However, none of the six animals started on cART on day four or five, across both RhCMV/SIV- and RhCMV/control-vaccinated groups, those rhesus macaques with SIV reservoirs most closely resembling those of prophylactically RhCMV/SIV-vaccinated and protected animals early in their course, showed post-cART viral rebound with up to nine months of follow-up. Moreover, at necropsy, these rhesus macaques showed little to no evidence of replication-competent SIV. These results suggest that the early SIV reservoir is limited in durability and that effective blockade of viral replication and spread in this critical time window by either pharmacologic or immunologic suppression may result in reduction, and potentially loss, of rebound-competent virus over a period of ~two years.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adoptive Transfer
  • Animals
  • Anti-Retroviral Agents / pharmacology
  • Anti-Retroviral Agents / therapeutic use*
  • Drug Therapy, Combination
  • Kinetics
  • Macaca mulatta
  • Necrosis
  • Simian Acquired Immunodeficiency Syndrome / drug therapy*
  • Simian Acquired Immunodeficiency Syndrome / virology*
  • Simian Immunodeficiency Virus / drug effects
  • Simian Immunodeficiency Virus / physiology*
  • Vaccination
  • Viral Vaccines / immunology
  • Viremia / drug therapy
  • Virus Replication


  • Anti-Retroviral Agents
  • Viral Vaccines