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Expression of CD4 by human hematopoietic progenitors
F Louache1, N Debili, A Marandin
1INSERM U 362, Institut Gustave Roussy, Villejuif, France.
Blood
|November 15, 1994
Summary
CD4 is present on human hematopoietic progenitors, predominantly on primitive CD34+ cells. This CD4 molecule is functional and binds HIV gp120, potentially explaining HIV-related cytopenias.
Area of Science:
- Immunology
- Hematology
- Cell Biology
Background:
- Murine hematopoietic stem cells and progenitors express low levels of CD4.
- The presence and role of CD4 on human hematopoietic progenitors remain largely uncharacterized.
Purpose of the Study:
- To investigate the expression and function of CD4 on human hematopoietic progenitors.
- To determine if CD4 expression correlates with stem cell-like properties.
- To explore the potential role of CD4 in HIV interactions with hematopoietic cells.
Main Methods:
- Two-color fluorescence flow cytometry analysis of CD34+ cells using anti-CD4 and anti-CD34 monoclonal antibodies.
- Phenotypic analysis of CD4 expression in various CD34+ subpopulations.
- In vitro functional assays including colony assays and long-term culture-initiating cell (LTC-IC) assays.
Main Results:
- A significant fraction (25-50%) of CD34+ cells showed weak CD4 expression.
- CD4 was predominantly expressed on phenotypically primitive CD34+ cells (CD38-/low, CD71low, Thy-1high, HLA-DR+/low).
- CD4low fraction was enriched in LTC-IC, which generated more primitive progenitors; CD4low cells bound HIV gp120.
Conclusions:
- CD4 is expressed on human hematopoietic progenitors, particularly on early primitive cells.
- The CD4 molecule on these cells is functional and interacts with HIV gp120.
- These findings may offer insights into HIV-induced cytopenias.