FIG. 2.
Dose-dependent induction of TNF-α by meningococcal LOS. LOS at a concentration of 0.056 pmol/ml (0.1 ng/ml), 0.56 pmol/ml (1 ng/ml), or 5.6 pmol/ml (10 ng/ml) from the parent strain NMB and synA, lst, pgm, rfaK, gmhX, and kdtA mutants (Table 1) were used to stimulate 106 differentiated THP-1 macrophages/ml overnight and assayed for TNF-α release. Decreased TNF-α release was seen with the KDO2-deficient meningococcal lipid A (kdtA). E. coli LPS (0111:B4), a LOS-deficient (lpxA) preparation, and unstimulated cells were used as controls.