Neisseria meningitidis-Induced Caspase-1 Activation in Human Innate Immune Cells Is LOS-Dependent

Figure 1

Involvement of LOS in N. meningitidis-induced caspase-1 activation in human primary neutrophils and monocytes. Innate immune cells in whole blood (a and b) or isolated human neutrophils (c) were stimulated for 2 h or 6 h, respectively, with the parental wild-type N. meningitidis FAM20 or its LOS-deficient mutant strain IpxA (MOI of 10). Caspase-1 activity of neutrophils (a) or monocytes (b) was determined as fold increase of median fluorescence intensity (MFI) by flow cytometry or quantified in isolated neutrophils (c) using a caspase-1 fluorometric assay. Bars represent , (a and b) and (c), of data normalized to unstimulated controls. Western blot (d) was used to detect caspase-1 in the uncleaved p45 form in primary human neutrophils stimulated with wild-type FAM20, lpxA mutant, or LPS (50 ng/mL) in combination with nigericin (10 μM). Results are shown as one representative out of three independent experiments (d).

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