Long-term control of simian immunodeficiency virus replication with central memory CD4+ T-cell preservation after nonsterile protection by a cytotoxic T-lymphocyte-based vaccine

J Virol. 2007 May;81(10):5202-11. doi: 10.1128/JVI.02881-06. Epub 2007 Mar 7.

Abstract

Induction of virus-specific CD8(+) cytotoxic T-lymphocyte (CTL) responses is a promising strategy for AIDS vaccine development. However, it has remained unclear if or how long-term viral containment and disease control are attainable by CTL-based nonsterile protection. Here, we present three rhesus macaques that successfully maintained Env-independent vaccine-based control of simian immunodeficiency virus (SIV) mac239 replication without disease progression for more than 3 years. SIV-specific neutralizing antibody induction was inefficient in these controllers. Vaccine-induced Gag-specific CTLs were crucial for the chronic as well as the primary viral control in one of them, whereas those Gag-specific CTL responses became undetectable and CTLs specific for SIV antigens other than Gag, instead, became predominant in the chronic phase in the other two controllers. A transient CD8(+) cell depletion experiment 3 years postinfection resulted in transient reappearance of plasma viremia in these two animals, suggesting involvement of the SIV non-Gag-specific CTLs in the chronic SIV control. This sustained, neutralizing antibody-independent viral control was accompanied with preservation of central memory CD4(+) T cells in the chronic phase. Our results suggest that prophylactic CTL vaccine-based nonsterile protection can result in long-term viral containment by adapted CTL responses for AIDS prevention.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS Vaccines / immunology*
  • Animals
  • Antibodies, Viral / blood
  • Antigens, Viral / immunology
  • CD4-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / immunology
  • Disease Progression
  • Flow Cytometry
  • Immunologic Memory
  • Lymphocyte Depletion
  • Macaca mulatta
  • Neutralization Tests
  • Simian Acquired Immunodeficiency Syndrome / immunology*
  • Simian Acquired Immunodeficiency Syndrome / virology*
  • Simian Immunodeficiency Virus / immunology
  • Simian Immunodeficiency Virus / physiology*
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocytes, Cytotoxic / immunology*
  • Viral Load
  • Viremia
  • Virus Replication* / immunology

Substances

  • AIDS Vaccines
  • Antibodies, Viral
  • Antigens, Viral