Fig 3.

CAMP and calprotectin mRNAs increase resistance to invasion by Listeria and Salmonella. Monolayers were transfected with mRNAs for 8, 24, or 48 h and then incubated for 2 h with L. monocytogenes ATCC 10403S at an MOI of 100:1 or S. Typhimurium ATCC 14028 at an MOI of 1:1. Cells were split 8 and 32 h after transfection, and then cells were incubated for another 16 h. Intracellular bacteria were recovered as described in Materials and Methods, and an antibiotic protection assay was used to determine the numbers of viable intracellular CFU. (A) Raw numbers of CFU per well after correcting for dilutions during the experimental protocol are shown as means ± SD for three to six replicates at 8 h. Numbers of CFU were normalized to the number of CFU in KB cells mock transfected with vehicle (set to 100) and are reported as means ± SD for three to six replicates at 8 (B), 24 (C), or 48 (D) h. Statistical analysis was performed using one-way ANOVA with Bonferroni's test. *, significantly decreased compared to vehicle control (P < 0.05).