FIG. 3.
Effect of exogenous IFN-γ on the rate and level of production of IL-10 (A and B), IL-6 (C and D), and IL-12 (E and F) induced by L-OspA and LPS stimulation. Vitamin D3-treated THP-1 cells (106/ml) were incubated with L-OspA (1 μg/ml) or LPS (1 μg/ml) in the presence or absence of various concentrations of human rIFN-γ. Cultures were incubated for 2, 8, 24, 48, and 120 h, after which specific cytokines in cell supernatants were collected and quantified by antibody-capture ELISA. The lower limit of detection of the ELISA was 15 pg/ml. Asterisks indicate significant difference from cells incubated with L-OspA and LPS alone (P < 0.01 to P < 0.0002). P values were calculated by use of Student's t test. Each bar represents the mean ± standard error of duplicate cultures. Data are representative of two separate experiments.