A novel protective MHC-I haplotype not associated with dominant Gag-specific CD8+ T-cell responses in SIVmac239 infection of Burmese rhesus macaques

PLoS One. 2013;8(1):e54300. doi: 10.1371/journal.pone.0054300. Epub 2013 Jan 14.

Abstract

Several major histocompatibility complex class I (MHC-I) alleles are associated with lower viral loads and slower disease progression in human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections. Immune-correlates analyses in these MHC-I-related HIV/SIV controllers would lead to elucidation of the mechanism for viral control. Viral control associated with some protective MHC-I alleles is attributed to CD8+ T-cell responses targeting Gag epitopes. We have been trying to know the mechanism of SIV control in multiple groups of Burmese rhesus macaques sharing MHC-I genotypes at the haplotype level. Here, we found a protective MHC-I haplotype, 90-010-Id (D), which is not associated with dominant Gag-specific CD8+ T-cell responses. Viral loads in five D+ animals became significantly lower than those in our previous cohorts after 6 months. Most D+ animals showed predominant Nef-specific but not Gag-specific CD8+ T-cell responses after SIV challenge. Further analyses suggested two Nef-epitope-specific CD8+ T-cell responses exerting strong suppressive pressure on SIV replication. Another set of five D+ animals that received a prophylactic vaccine using a Gag-expressing Sendai virus vector showed significantly reduced viral loads compared to unvaccinated D+ animals at 3 months, suggesting rapid SIV control by Gag-specific CD8+ T-cell responses in addition to Nef-specific ones. These results present a pattern of SIV control with involvement of non-Gag antigen-specific CD8+ T-cell responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD8-Positive T-Lymphocytes / immunology*
  • Genome, Viral / genetics
  • Haplotypes / genetics*
  • Macaca mulatta
  • Major Histocompatibility Complex / genetics*
  • Simian Acquired Immunodeficiency Syndrome / immunology
  • Simian Immunodeficiency Virus / genetics*
  • Simian Immunodeficiency Virus / immunology*
  • Simian Immunodeficiency Virus / pathogenicity

Grants and funding

This work was supported by grants-in-aid from the Ministry of Education, Culture, Sports, Science, and Technology, and grants-in-aid from the Ministry of Health, Labor, and Welfare. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.