(a-c) hRegIIIα pore formation is inhibited by
lipopolysaccharide. (a) 10 μM hRegIIIα
was added to liposomes composed of lipids from an E. coli total
lipid extract or from PC/PS as a control. (b) 10 μM
hRegIIIα was added to liposomes (100 μM lipid) in the presence
of varying LPS concentrations. (c) 10 μM hRegIIIα
was added to ∼104 cfu of log phase L.
monocytogenes in the presence of varying LPS concentrations. The
assay was carried out at 37°C for 2 hours, and surviving bacteria were
quantified by dilution plating. Assays were done in triplicate. Results in
a-care representative of two independent experiments.
(d-e) The hRegIIIα N-terminal prosegment limits toxicity
toward mammalian cells. (d) hRegIIIα was added
to MODE-K cells and cytotoxicity was determined by quantifying lactate
dehydrogenase (LDH) release. LDH activity was assessed by spectrophotometric
detection of an enzymatic product of LDH at 492 nm. (e) 10
μM hRegIIIα or pro-hRegIIIα was added to MODE-K cells
and LDH release was quantified. Maximum LDH release was determined by treating
cells with NP-40 detergent.