title: In vitro exposure to human immunodeficiency virus type 1 induces apoptotic cell death of the factor-dependent TF-1 hematopoietic cell line.
abstract: In this study, we evaluated the effect of a short-term exposure (2 hours) to two different lymphocytotropic strains of human immunodeficiency virus type 1 (HIV-1; HIVIIIB and ICR-3) on the survival of a factor-dependent CD34+ hematopoietic progenitor cell line (TF-1). At flow cytometry analysis, a significant (P < .05) increase in the frequency of apoptotic cell death was observed in HIV-1-treated TF-1 cells, supplemented with low doses of either interleukin-3 (IL-3; 0.02 to 1 ng/mL) or granulocyte-macrophage colony-stimulating factor (GM-CSF; 0.02 to 0.2 ng/mL) with respect to mock-treated cells. On the other hand, higher doses of both cytokines or combinations of suboptimal concentrations of IL-3 plus GM-CSF (eg, 0.2, plus 0.2 ng/mL) completely reversed the HIV-1-induced increase of apoptosis. Remarkably, no signs of productive or latent virus replication were ever observed in HIV-1-treated TF-1 cells up to 16 days of liquid culture. In parallel experiments, the in vitro exposure to HIVIIIB induced a significant and progressive increase of apoptotic death in purified bone marrow CD34+ cells, seeded in liquid cultures in the presence of 1 ng/mL IL-3. The HIV-1-induced apoptosis of TF-1 cells was likely triggered by the simple interaction of HIV-1 envelope glycoprotein gp120 with CD4 receptor, which was expressed at a low level on the surface of TF-1 cells. In fact, treatment of TF-1 cells with recombinant gp120 plus a polyclonal anti-gp120 antibody or with anti-CD4 monoclonal antibody plus rabbit antimouse IgG significantly increased the percentage of apoptotic death. These data suggest that HIV-1, and perhaps also free gp120 in the presence of anti-gp120 antibody; could play a direct role in the pathogenesis of peripheral blood cytopenias in acquired immunodeficiency syndrome patients by inducing apoptotic death of hematopoietic progenitor cells without the need of a direct infection.
authors.affiliation: Institute of Human Anatomy, University of Ferrara, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Zauli
authors.forename: M
authors.initials: M
authors.lastname: Vitale
authors.forename: M C
authors.initials: MC
authors.lastname: Re
authors.forename: G
authors.initials: G
authors.lastname: Furlini
authors.forename: L
authors.initials: L
authors.lastname: Zamai
authors.forename: E
authors.initials: E
authors.lastname: Falcieri
authors.forename: D
authors.initials: D
authors.lastname: Gibellini
authors.forename: G
authors.initials: G
authors.lastname: Visani
authors.forename: B R
authors.initials: BR
authors.lastname: Davis
authors.forename: S
authors.initials: S
authors.lastname: Capitani
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34; D017209:Apoptosis; D015704:CD4 Antigens / Q000032:analysis; D002460:Cell Line; D005434:Flow Cytometry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D015699:HIV Envelope Protein gp120 / Q000494:pharmacology; D015497:HIV-1 / Q000472:pathogenicity*; D006412:Hematopoietic Stem Cells / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120; D007377:Interleukin-3; D016178:Granulocyte-Macrophage Colony-Stimulating Factor