Cytokine suppressive effects of 3-HAA. A: Dose response of 3-HAA. Primary human astrocyte cultures were treated with varying concentrations of 3-HAA (0 to 100 μmol/L) and 10 ng/mL of IL-1β. Culture supernatants were collected 24 hours later, and the levels of the two α-chemokines IP-10 and IL-8 were determined by ELISA. Data shown are mean ± SD from triplicate cultures. IP-10 production was dose dependently suppressed by 3-HAA, but IL-8 was not affected by 3-HAA. B and C: 3-HAA suppression of TNF-α and IP-10 in microglia and astrocytes. Primary human microglia (B) were stimulated with PIC (10 μg/mL) or LPS (100 ng/mL) with or without 3-HAA (100 μmol/L). Astrocytes (C) were stimulated with IL-1 (10 ng/mL), PIC (10 μg/mL), or IL-1/IFN-γ (10 ng/mL) with or without 3-HAA (100 μmol/L). Levels of TNF-α, IP-10, and IL-8 were measured in triplicate wells in each culture, then the percentage of inhibition by 3-HAA was calculated from the mean values. Each symbol represents an independent experiment using different brain case. P values were obtained using the single-sample t-test.