Human Immunodeficiency Virus Type 1 Envelope Glycoprotein Gp120-mediated Killing of Human Haematopoietic Progenitors (CD34+ Cells)

The effects of human immunodeficiency virus type 1 (HIV-1) and recombinant envelope glycoprotein gp120 on the in vitro growth of enriched human haematopoietic progenitors (CD34+ cells) have been investigated. A 2 h exposure to HIV-1 resulted in a progressive and significant reduction of viable CD34+ cell number in liquid cultures and of granulocyte-macrophage, erythroid and megakaryocytic progenitors in semisolid cultures. In virus-treated CD34+ cells, no signs of active virus replication were observed and the possibility of latent infection was excluded by quantitative polymerase chain reaction. Recombinant HIV-1 envelope glycoprotein gp120 added to CD34+ cell cultures displayed a dose-dependent inhibitory activity on CD34+ cell viability. Neutralizing antibody against gp120 was able to block completely the inhibitory activity on CD34+ cells of either HIV-1 or recombinant gp120. These results demonstrate that HIV-1 envelope glycoprotein gp120 has a direct cytotoxic effect on CD34+ cells.