Down regulation of stem cell colony formation by purified CD8 lymphocytes and CD8 conditioned medium: Potential importance for bone marrow transplantation in leukemia

Yair Gazitt, Yun Ju He

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

A methodology for selection of the CD8 cell subset from the peripheral blood and bone marrow mononuclear cells was developed using anti-T8 (CD8) antibody and magnetic microspheres coated with anti-mouse IgG. Following optimization of antibody: cell binding ratio and microsphere : cell ratios, CD8+-cells in the peripheral blood and bone marrow were effectively removed, with an overall final recovery of 34.9% ± 8.6% and 56% ± 8.5% respectively with complete recovery of stem cells and very little contamination with effector cells. CD8+-depleted cell preparations demonstrated a 3-4 fold increase in CFU-C and CFU-E colony formation over non-depleted preparations when stimulated with G-CSF, GM-CSF or IL-3 and erythropoietin. The largest increase in colony formation was evident when IL-3 was used to stimulate colony formation. Purified autologous CD8+ T-cells or culture supernatant from in vitro cultures of purified autologous CD8+ T-cells added back to CD8 depleted preparations, induced 20%90% suppression of CFU-C and CFU-E colony formation in a dose dependent manner. Colony formation by CD34+ cells, purified by anti CD34 antibodies and magnetic microspheres, were also inhibited by either pure CD8+-cell populations or CD8-culture supernatant. Preliminary fractionation studies indicate that the inhibitory factor is a protein of >50kd. In contrast, when purified autologous CD4+ cells were added to purified CD34+ stem cells, an increase (<50% in colony formation was observed. These results, taken together, suggest that CD8+ T-cells are negative effectors of normal hematopoiesis whereas CD4+ T-cells function as positive effectors.

Original languageEnglish (US)
Pages (from-to)117-127
Number of pages11
JournalLeukemia and Lymphoma
Volume8
Issue number1-2
DOIs
StatePublished - 1992
Externally publishedYes

Keywords

  • Bone marrow
  • CD8
  • Colony formation
  • Down regulation
  • Immunomagnetic selection

ASJC Scopus subject areas

  • Hematology
  • Oncology
  • Cancer Research

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