Infection with "escaped" virus variants impairs control of simian immunodeficiency virus SIVmac239 replication in Mamu-B*08-positive macaques

J Virol. 2009 Nov;83(22):11514-27. doi: 10.1128/JVI.01298-09. Epub 2009 Sep 2.

Abstract

An understanding of the mechanism(s) by which some individuals spontaneously control human immunodeficiency virus (HIV)/simian immunodeficiency virus replication may aid vaccine design. Approximately 50% of Indian rhesus macaques that express the major histocompatibility complex (MHC) class I allele Mamu-B*08 become elite controllers after infection with simian immunodeficiency virus SIVmac239. Mamu-B*08 has a binding motif that is very similar to that of HLA-B27, a human MHC class I allele associated with the elite control of HIV, suggesting that SIVmac239-infected Mamu-B*08-positive (Mamu-B*08+) animals may be a good model for the elite control of HIV. The association with MHC class I alleles implicates CD8+ T cells and/or natural killer cells in the control of viral replication. We therefore introduced point mutations into eight Mamu-B*08-restricted CD8+ T-cell epitopes to investigate the contribution of epitope-specific CD8+ T-cell responses to the development of the control of viral replication. Ten Mamu-B*08+ macaques were infected with this mutant virus, 8X-SIVmac239. We compared immune responses and viral loads of these animals to those of wild-type SIVmac239-infected Mamu-B*08+ macaques. The five most immunodominant Mamu-B*08-restricted CD8+ T-cell responses were barely detectable in 8X-SIVmac239-infected animals. By 48 weeks postinfection, 2 of 10 8X-SIVmac239-infected Mamu-B*08+ animals controlled viral replication to <20,000 viral RNA (vRNA) copy equivalents (eq)/ml plasma, while 10 of 15 wild-type-infected Mamu-B*08+ animals had viral loads of <20,000 vRNA copy eq/ml (P = 0.04). Our results suggest that these epitope-specific CD8+ T-cell responses may play a role in establishing the control of viral replication in Mamu-B*08+ macaques.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Line
  • DNA Primers
  • Epitopes, T-Lymphocyte / immunology
  • Genes, MHC Class I / immunology
  • Genetic Variation / immunology
  • Histocompatibility Antigens Class I / immunology*
  • Macaca mulatta / immunology
  • Macaca mulatta / virology
  • Mutagenesis, Site-Directed
  • Simian Acquired Immunodeficiency Syndrome / virology*
  • Simian Immunodeficiency Virus / genetics
  • Simian Immunodeficiency Virus / pathogenicity*
  • Viral Load
  • Virus Replication / genetics*

Substances

  • DNA Primers
  • Epitopes, T-Lymphocyte
  • Histocompatibility Antigens Class I