Relationship between cytokine-dependent cell cycle progression and MHC class II antigen expression by human CD34+ HLA-DR- bone marrow cells

E. F. Srour, J. E. Brandt, T. Leemhuis, C. B. Ballas, R. Hoffman

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

Human CD34+ HLA-DR- bone marrow cells constitute a phenotypically homogeneous population of quiescent cells. More than 97% of CD34+ HLA-DR- cells reside in the G0/G1 phase of the cell cycle. The in vitro effects of two cytokines, IL-1α and IL-3, alone or in combination, on the viability, cell cycle status and acquisition of HLA-DR by this cell population were examined. Cell viability was preserved in cultures receiving cytokines, but declined steadily in cultures deprived of exogenous IL. Over a period of 4 days, IL-3 progressively induced the expression of HLA-DR although driving corresponding numbers of cells into S and G2 + M. Although IL-1α induced the expression of HLA-DR, it was not as effective as IL-3 in promoting the exit of these cells from G0/G1. Combinations of IL-1α and IL-3, however, exerted an even greater effect on promoting both HLA-DR expression and entry of cells into active phases of the cell cycle. Simultaneous measurement of HLA-DR expression and cell cycle status in response to IL-1α and IL-3 indicated that the majority of de novo expression of HLA-DR occurred in cells that remained in G0/G1. CD34+ HLA-DR- cells cultured with IL-1α and IL-3 but arrested in G0/G1 by hydroxyurea were still capable of expressing HLA-DR, demonstrating that the acquisition of HLA-DR was independent of the entry of these cells into active phases of the cell cycle. These data indicate that the survival, HLA-DR expression, and cell cycle status of human CD34+ HLA-DR- bone marrow cells are governed by regulatory cytokines such as IL-1α and IL-3. In addition, the entry of these cells into active phases of the cell cycle does not seem to be a prerequisite for the expression of HLA-DR, nor does it seem that the acquisition of HLA-DR by hematopoietic progenitor cells is a marker of cells entering the S phase of the cell cycle.

Original languageEnglish (US)
Pages (from-to)815-820
Number of pages6
JournalJournal of Immunology
Volume148
Issue number3
StatePublished - Jan 1 1992

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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