Combined effect of IL-6, IFN-γ, and MCP-1 on neuroglial (HFN and HFA) damage. (A, B) HFA and (D, E) HFN were treated with different doses of IL-6 (75 to 750 pg/ml) or IFN-γ (100 to 1,000 pg/ml) either alone or together (150 pg/ml IL-6 and 200 pg/ml IFN-γ). Toxicity was determined by LDH assay at 48 h after treatment. (C) IL-6 and IFN-γ, alone or in combination with MCP-1 (5 ng/ml), were tested in modulating mitochondrial membrane potential in HIV-1-treated astrocytes after 12 h of treatment. (F) Dose response of MCP-1 (1–25 ng/ml) in inducing neuroglial toxicity. (G, H), Effect of IL-6 and IFN-γ in combinations with HIV-1 on the (G) toxicity profile (LDH) and (H) viability (MTT/QuantiBlue) of neurons at 48 h after treatment. Effects of IL-6, IFN-γ, and MCP-1 in combination with HIV-1 in modulating (I) toxicity (LDH) and (J) viability (QuantiBlue) at 48 h post-treatment in neurons. MCP, monocyte chemotactic protein; HFN, human fetal neurons; HFA, human fetal astrocytes; LDH, lactate dehydrogenase.