FIG. 5.

Comparison of mean percentage (±SEM) of neuronal death induced by CM from macrophages infected with HIV-1 JR-FL, uninfected macrophages (control), or NMDA treatment (A), CM harvested from different time points after infection (B), and different times of exposure of neuronal cultures to CM (C). JR-FL induced neurotoxicity at various dilutions of CM (A), with maximum neuronal death at a 50 to 66% dilution. Neuronal cultures treated with 50% CM from uninfected macrophages showed significantly less neuronal death than CM at the same concentration from JR-FL-infected macrophages (Student’s t test, P < 0.001). A decline in neuronal killing was observed with 50% CM harvested at later time points postinfection (B). The extent of neuronal death did not change with different times of exposure to CM, harvested at 3 days postinfection (C). Macrophages were infected at an input titer of 10³ TCID₅₀/0.1 ml.