Inhibitory effect of HIV-1 envelope glycoproteins gp120 and gp160 on the in vitro growth of enriched (CD34+) hematopoietic progenitor cells

The effect of increasing concentrations (from 0.01 to 10 μg/ml) of HIV-1 envelope glycoproteins gp160, gp120, gp41 and core protein p24 was evaluated on the in vitro growth of enriched hematopoietic progenitors (CD34⁺ cells). Both gp120 and gp160, at concentrations from 0.01 to 10 μg/ml, caused a progressive and significant (p+ cell count in liquid cultures supplemented with 2 ng/ml of human recombinant (r) interleukin-3 (IL-3), evaluated by means of Trypan-blue exclusion and [³H]thymidine ([³H]TdR) incorporation. In the absence of rIL-3, no inhibitory effects were observed even at the highest gp160 and gp120 concentrations explored (10 μg/ml). On the contrary, gp41 and p24 did not affect the number of viable CD34⁺ cells, either in the presence or in the absence of rIL-3. Moreover, gp160 and gp120, but not gp41 and p24, significantly (p+ cell surface, independently of an infectious process.