Role of complement and antibodies in controlling infection with pathogenic simian immunodeficiency virus (SIV) in macaques vaccinated with replication-deficient viral vectors

Retrovirology. 2009 Jun 21;6:60. doi: 10.1186/1742-4690-6-60.


Background: We investigated the interplay between complement and antibodies upon priming with single-cycle replicating viral vectors (SCIV) encoding SIV antigens combined with Adeno5-SIV or SCIV pseudotyped with murine leukemia virus envelope boosting strategies. The vaccine was applied via spray-immunization to the tonsils of rhesus macaques and compared with systemic regimens.

Results: Independent of the application regimen or route, viral loads were significantly reduced after challenge with SIVmac239 (p < 0.03) compared to controls. Considerable amounts of neutralizing antibodies were induced in systemic immunized monkeys. Most of the sera harvested during peak viremia exhibited a trend with an inverse correlation between complement C3-deposition on viral particles and plasma viral load within the different vaccination groups. In contrast, the amount of the observed complement-mediated lysis did not correlate with the reduction of SIV titres.

Conclusion: The heterologous prime-boost strategy with replication-deficient viral vectors administered exclusively via the tonsils did not induce any neutralizing antibodies before challenge. However, after challenge, comparable SIV-specific humoral immune responses were observed in all vaccinated animals. Immunization with single cycle immunodeficiency viruses mounts humoral immune responses comparable to live-attenuated immunodeficiency virus vaccines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviruses, Human / genetics
  • Aerosols
  • Animals
  • Antibodies, Viral / blood
  • Antibodies, Viral / immunology*
  • Complement System Proteins / immunology*
  • Genetic Vectors
  • Leukemia Virus, Murine / genetics
  • Macaca mulatta
  • Neutralization Tests
  • Palatine Tonsil / virology
  • SAIDS Vaccines / immunology*
  • Simian Acquired Immunodeficiency Syndrome / prevention & control*
  • Simian Immunodeficiency Virus / genetics
  • Simian Immunodeficiency Virus / immunology*
  • Viral Load


  • Aerosols
  • Antibodies, Viral
  • SAIDS Vaccines
  • Complement System Proteins