Selective elimination of immunosuppressive T cells in patients with multiple myeloma

Leukemia. 2021 Sep;35(9):2602-2615. doi: 10.1038/s41375-021-01172-x. Epub 2021 Feb 17.

Abstract

Elimination of suppressive T cells may enable and enhance cancer immunotherapy. Here, we demonstrate that the cell membrane protein SLAMF7 was highly expressed on immunosuppressive CD8+CD28-CD57+ Tregs in multiple myeloma (MM). SLAMF7 expression associated with T cell exhaustion surface markers and exhaustion-related transcription factor signatures. T cells from patients with a high frequency of SLAMF7+CD8+ T cells exhibited decreased immunoreactivity towards the MART-1aa26-35*A27L antigen. A monoclonal anti-SLAMF7 antibody (elotuzumab) specifically depleted SLAMF7+CD8+ T cells in vitro and in vivo via macrophage-mediated antibody-dependent cellular phagocytosis (ADCP). Anti-SLAMF7 treatment of MM patients depleted suppressive T cells in peripheral blood. These data highlight SLAMF7 as a marker for suppressive CD8+ Treg and suggest that anti-SLAMF7 antibodies can be used to boost anti-tumoral immune responses in cancer patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Animals
  • Antibodies, Monoclonal, Humanized / therapeutic use*
  • Antineoplastic Agents / therapeutic use
  • Apoptosis
  • Cell Proliferation
  • Female
  • Humans
  • Lymphocyte Depletion / methods*
  • Male
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Middle Aged
  • Multiple Myeloma / immunology*
  • Multiple Myeloma / pathology
  • Multiple Myeloma / therapy
  • Prognosis
  • Signaling Lymphocytic Activation Molecule Family / genetics
  • Signaling Lymphocytic Activation Molecule Family / metabolism*
  • Tumor Cells, Cultured
  • Xenograft Model Antitumor Assays

Substances

  • Antibodies, Monoclonal, Humanized
  • Antineoplastic Agents
  • SLAMF7 protein, human
  • Signaling Lymphocytic Activation Molecule Family
  • elotuzumab