Human immunodeficiency virus type l (H1V-1) gp120-induced increases in reactive oxygen species in human U937 cells

H3V-1 coat protein gp!20 appears to help mediate viral entry and viral tropism, and have neurotoxic properties. Qne mechanism for neurotoxicity may be gp!20-induced formation of reactive oxygen species (ROS). Using a thiobarbituric acid assay, we determined, in human myelomonocytic U937 cells, the extent to which ROS were formed by recombinant gp!20 (H1V-13B) and, for comparison, hypoxanthine/xanthine (H/X). gp!20 was as effective as H/X at inducing ROS production; EC50 value for gp!20 was approximately 11 pM. Co-incubation of gp!20 with polyclonal antibody to gp!20 significantly (p<0.05) inhibited gp!20-induced ROS production by 42%. gp!20- and H/X-induced ROS production were almost equally blocked by a variety of antioxidants and free radical scavengers. gp!20induced ROS production was significantly (pO.Ol) inhibited 78% by nondialyzed and 100% by dialyzed catalase/superoxide dismutase (1000/300 units/ml), 78% by 50 uM desferrioxamine (p<0.01), 53% by 40 uM Vitamin E (p<0.05), and 82% by 100 uM EDTA (p<0.01). The nucleoside transport inhibitor dipyridamole (Persantin™) significantly (p<0.05) inhibited gp!20-induced ROS production at concentrations as low as 0.3 μM; apparent IC₅₀ value was 1.0 μM.