C-terminal deletion of S100A9 increases resistance to Listeria
and Salmonella invasion. KB-sham,
KB-S100A8/A91–114, KB-S100A8/A91–112, and
KB-S100A8/A91–99 were analyzed for bacterial invasion using
an antibiotic protection assay as described under “Experimental
Procedures.” Monolayers were incubated with L. monocytogenes
ATCC 10403S (A) or S. typhimurium ATCC 14028 (B) at
an m.o.i. of 100:1 and 1:1, respectively, for 2 h. Each experiment was
performed in triplicate wells. Values are means ± S.E. of viable
intracellular bacteria, relative to KB-sham (100%) from at least three
independent experiments. C, immunofluorescence staining for
intracellular and extracellular Listeria in KB-sham,
KB-S100A8/A91–114, KB-S100A8/A91–112, and
KB-S100A8/A91–99 transfectants. Monolayers were incubated
with L. monocytogenes for 2 h. The intracellular bacteria were
enumerated and reported as means ± S.E. relative to KB-sham (100%). The
results shown are from three independent experiments (*, p
< 0.05; **, p < 0.01; #, p < 0.001).