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.