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Volume 9 Supplement 2

AIDS Vaccine 2012

Efficacy of vaccine-induced Vif-specific CTL responses against SIVmac239 infection: implications for antigen design in AIDS vaccines


Optimization of antigens as well as delivery system is crucial for development of an effective T-cell based AIDS vaccine. Our recent results suggested higher anti-viral efficacy of Vif- and Nef-specific CTLs as well as Gag-specific ones (JEM 199:1709, 2004; AIDS 24:2777, 2010). Here, we examined efficacy of Gag-specific or Vif/Nef-specific CTL induction by vaccination against SIV infection.


All 17 animals used in this study were Burmese rhesus macaques sharing MHC-I haplotype 90-010-Ie, which mostly show typical AIDS progression after SIVmac239 challenge (geometric means of setpoint plasma viral loads: 10^5 copies/ml; mean survival periods: 2 years). These animals were divided into three groups consisting of unvaccinated (n = 6), Gag-vaccinated (n = 5), and Vif/Nef-vaccinated (n = 6); the latter two were subjected to DNA-prime/Sendai virus vector-boost vaccination. We compared these three groups after an intravenous SIVmac239 challenge.


After challenge, 3 out of 5 Gag-vaccinated and 3 out of 6 Vif/Nef-vaccinated animals controlled SIV replication. The SIV control was associated with Gag-specific CTL responses in the former and Vif-specific CTL responses in the latter.


This is the first report indicating efficacy of vaccine-induced Vif-specific CTL responses against SIV replication. Our results imply that not only Gag but also Vif may be a promising antigen for T-cell based AIDS vaccines.

Author information

Correspondence to N Iwamoto.

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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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About this article


  • Delivery System
  • Viral Load
  • Rhesus Macaque
  • Geometric Means
  • Survival Period