INHIBITORY EFFECT OF HIV-1 ENVELOPE GLYCOPROTEINS GP120 AND GP160 ON THE INVITRO GROWTH OF ENRICHED (CD34+) HEMATOPOIETIC PROGENITOR CELLS

The effect of increasing concentrations (from 0.01 to 10-mu-g/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-mu-g/ml, caused a progressive and significant (p < 0.05) decrease in viable CD34+ 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 [H-3]thymidine ([H-3]TdR) incorporation. In the absence of rIL-3, no inhibitory effects were observed even at the highest gp160 and gp120 concentrations explored (10-mu-g/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 < 0.05) inhibited the in vitro growth of granulomacrophage progenitors (CFU-GM) in a dose-dependent fashion. These data clearly demonstrate that HIV-1 envelope glycoproteins inhibit the growth of purified hematopoietic progenitors. We propose that HIV-1 can impair hematopoiesis through the interaction of gp120/gp160 with CD34+ cell surface, independently of an infectious process.