Identification of a CD11b+/Gr-1+/CD31+ myeloid progenitor capable of activating or suppressing CD8+ T cells

V. Bronte, E. Apolloni, A. Cabrelle, R. Ronca, P. Serafini, P. Zamboni, N. P. Restifo, P. Zanovello

Research output: Contribution to journalArticlepeer-review

421 Scopus citations

Abstract

Apoptotic death of CD8+ T cells can be induced by a population of inhibitory myeloid cells that are double positive for the CD11b and Gr-1 markers. These cells are responsible for the immunosuppression observed in pathologies as dissimilar as tumor growth and overwhelming infections, or after immunization with viruses. The appearance of a CD11b+/Gr-1+ population of inhibitory macrophages (iMacs) could be attributed to high levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) in vivo. Deletion of iMacs in vitro or in vivo reversed the depression of CD8+ T-cell function. We isolated iMacs from the spleens of immunocompromised mice and found that these cells were positive for CD31, ER-MP20 (Ly-6C), and ER-MP58, markers characteristic of granulocyte/monocyte precursors. Importantly, although iMacs retained their inhibitory properties when cultured in vitro in standard medium, suppressive functions could be modulated by cytokine exposure. Whereas culture with the cytokine interleukin 4 (IL-4) increased iMac inhibitory activity, these cells could be differentiated into a nonadherent population of fully mature and highly activated dendritic cells when cultured in the presence of IL-4 and GM-CSF. A common CD31+/CD11b+/Gr-1+ progenitor can thus give rise to cells capable of either activating or inhibiting the function of CD8+ T lymphocytes, depending on the cytokine milieu that prevails during antigen-presenting cell maturation. (C) 2000 by The American Society of Hematology.

Original languageEnglish (US)
Pages (from-to)3838-3846
Number of pages9
JournalBlood
Volume96
Issue number12
StatePublished - Dec 1 2000
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology

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