FIGURE 4.

Production of IL-6 by MM6 cells upon incubation with mutant LPS. MM6 cells were incubated with the indicated concentrations of LPS preparations from lgtB⁻ (open circle), lgtB⁻ pagL⁺ (closed square), and galE⁻ lpxL1⁻ (open triangle) mutants of N. meningitidis for 18 h at 37 °C in a 5% CO₂-humidified atmosphere. As control, cells were incubated in supplemented IMDM only (asterisk). The concentration of IL-6 in supernatants was determined by ELISA. Data points represent the average of quadruplicate determinations. Error bars represent the standard deviation.