LOX-1 as a natural IFN-alpha-mediated signal for apoptotic cell uptake and antigen presentation in dendritic cells

Blood. 2010 Feb 25;115(8):1554-63. doi: 10.1182/blood-2009-07-234468. Epub 2009 Dec 15.

Abstract

The identification of molecules responsible for apoptotic cell (AC) uptake by dendritic cells (DCs) and induction of T-cell immunity against AC-associated antigens is a challenge in immunology. DCs differentiated in the presence of interferon-alpha (IFN-alpha-conditioned DCs) exhibit a marked phagocytic activity and a special attitude in inducing CD8(+) T-cell response. In this study, we found marked overexpression of the scavenger receptor oxidized low-density lipoprotein receptor 1 (LOX-1) in IFN-alpha-conditioned DCs, which was associated with increased levels of genes belonging to immune response families and high competence in inducing T-cell immunity against antigens derived from allogeneic apoptotic lymphocytes. In particular, the capture of ACs by IFN-alpha DCs led to a substantial subcellular rearrangement of major histocompatibility complex class I and class II molecules, along with enhanced cross-priming of autologous CD8(+) T cells and CD4(+) T-cell activation. Remarkably, AC uptake, CD8(+) T-cell cross-priming, and, to a lesser extent, priming of CD4(+) T lymphocytes were inhibited by a neutralizing antibody to the scavenger receptor LOX-1 protein. These results unravel a novel LOX-1-dependent pathway by which IFN-alpha can, under both physiologic and pathologic conditions, render DCs fully competent for presenting AC-associated antigens for cross-priming CD8(+) effector T cells, concomitantly with CD4(+) T helper cell activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigen Presentation / immunology*
  • Apoptosis / drug effects*
  • Apoptosis / immunology
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Cells, Cultured
  • Dendritic Cells / immunology*
  • Humans
  • Immunity, Cellular / drug effects
  • Immunologic Factors / immunology
  • Immunologic Factors / pharmacology*
  • Interferon-alpha / immunology
  • Interferon-alpha / pharmacology*
  • Lymphocyte Activation / drug effects
  • Scavenger Receptors, Class E / immunology*
  • Signal Transduction / drug effects*
  • Signal Transduction / immunology

Substances

  • Immunologic Factors
  • Interferon-alpha
  • OLR1 protein, human
  • Scavenger Receptors, Class E