DC-NK cell cross talk as a novel CD4+ T-cell-independent pathway for antitumor CTL induction

Blood. 2005 Jul 1;106(1):338-44. doi: 10.1182/blood-2004-09-3775. Epub 2005 Mar 15.

Abstract

It is generally accepted that priming of antitumor CD8+ cytotoxic T lymphocytes (CTLs) needs help that can be provided by CD4+ T cells. We show that interactions between dendritic cells (DCs) and natural killer (NK) cells can bypass the T helper arm in CTL induction. Bone marrow-derived DCs caused rejection of the A20 lymphoma and induced tumor-specific long-term memory, although they were not loaded with tumor-derived antigen. Experiments using CD40(-) knock-out mice and cell depletion showed that this effect did not require CD4+ cells. Both primary rejection and long-term CTL memory were the result of NK cell activation by DCs. NK cytotoxicity, which was necessary for primary rejection, was dependent on expression of natural killer group 2 D (NKG2D) ligands on tumor cells. Blocking of these ligands using NKG2D tetramers abrogated tumor killing in vitro and in vivo. The long-term response was due to CTLs directed against antigen(s) expressed on A20 and in vitro-differentiated DCs. The mechanism leading to CD4+ helper cell-independent CTL responses was elucidated as a cascade that was initiated by NK cell activation. This pathway was dependent on inter-feron-gamma expression and involved priming endogenous DCs for interleukin-12 production. Our data suggest a novel pathway linking innate and adaptive immunity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD4-Positive T-Lymphocytes / immunology*
  • CD40 Antigens / genetics
  • Cell Communication / immunology*
  • Cell Line, Tumor
  • Colonic Neoplasms / immunology
  • Dendritic Cells / immunology*
  • Humans
  • Immunologic Memory
  • Interferon-gamma / immunology
  • Interleukin-12 / immunology
  • Killer Cells, Natural / immunology*
  • Lymphoma, B-Cell / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, SCID
  • T-Lymphocytes, Cytotoxic / immunology

Substances

  • CD40 Antigens
  • Interleukin-12
  • Interferon-gamma