FIG. 4.

The effect of meningococcal LOS structure on nitric oxide induction in macrophages. RAW macrophages (10⁶ cells/ml) were stimulated overnight with meningococcal LOS NMB and synA, lst, pgm, rfaK, gmhX, kdtA, and kpsF mutants at 0.56 pmol/ml (Table 1). A preparation from the LOS-deficient mutant (lpxA) and unstimulated cells were used as controls. Nitrite concentration in cell supernatants was detected with the Griess method. Error bars represent SD from the mean, and the data are from four different readings and are representative of other similar experiments.