A viral CTL escape mutation leading to immunoglobulin-like transcript 4-mediated functional inhibition of myelomonocytic cells

J Exp Med. 2007 Nov 26;204(12):2813-24. doi: 10.1084/jem.20061865. Epub 2007 Nov 19.

Abstract

Viral mutational escape can reduce or abrogate recognition by the T cell receptor (TCR) of virus-specific CD8+ T cells. However, very little is known about the impact of cytotoxic T lymphocyte (CTL) epitope mutations on interactions between peptide-major histocompatibility complex (MHC) class I complexes and MHC class I receptors expressed on other cell types. Here, we analyzed a variant of the immunodominant human leukocyte antigen (HLA)-B2705-restricted HIV-1 Gag KK10 epitope (KRWIILGLNK) with an L to M amino acid substitution at position 6 (L6M), which arises as a CTL escape variant after primary infection but is sufficiently immunogenic to elicit a secondary, de novo HIV-1-specific CD8+ T cell response with an alternative TCR repertoire in chronic infection. In addition to altering recognition by HIV-1-specific CD8+ T cells, the HLA-B2705-KK10 L6M complex also exhibits substantially increased binding to the immunoglobulin-like transcript (ILT) receptor 4, an inhibitory MHC class I-specific receptor expressed on myelomonocytic cells. Binding of the B2705-KK10 L6M complex to ILT4 leads to a tolerogenic phenotype of myelomonocytic cells with lower surface expression of dendritic cell (DC) maturation markers and co-stimulatory molecules. These data suggest a link between CTL-driven mutational escape, altered recognition by innate MHC class I receptors on myelomonocytic cells, and functional impairment of DCs, and thus provide important new insight into biological consequences of viral sequence diversification.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acquired Immunodeficiency Syndrome / genetics
  • Acquired Immunodeficiency Syndrome / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / virology*
  • HIV / genetics
  • HIV / immunology*
  • HIV Infections / immunology*
  • HLA-B27 Antigen / genetics
  • Histocompatibility Antigens Class I / genetics
  • Humans
  • Monocytes / immunology*
  • Monocytes / virology
  • Mutation
  • Myeloid Cells / immunology*
  • Myeloid Cells / virology
  • Receptors, Antigen, T-Cell / genetics
  • T-Lymphocytes, Cytotoxic / immunology*
  • T-Lymphocytes, Cytotoxic / virology*

Substances

  • HLA-B27 Antigen
  • Histocompatibility Antigens Class I
  • Receptors, Antigen, T-Cell