LL-37 is protective against RSV-induced cell death.

<p>HEp-2 cells were treated with LL-37 at 0–50 µg/ml, a scrambled control LL-37 at 50 µg/ml (Scr 50), or ribavirin (200 µM), in the presence (a & c) or absence (b) of simultaneous infection with RSV (MOI = 0.005). Cells were incubated for 2 hours at 37°C, washed and placed in fresh medium. In some wells LL-37 or ribavirin was added again at this point (c; “continuous treatment”). Cells were cultured at 37°C for 24 hours (a) or 5 days (b & c), after which the number of viable metabolically active cells was assessed using an MTT assay with measurement of optical density at 450 nm, expressed as a percentage of untreated infected (a & c) or untreated (b) cells. Results are shown as mean +/− SEM of n = 3-4. The data were analysed by 1-way ANOVAs with Dunnett Multiple Comparison Post-tests comparing peptide concentrations against the “no peptide” control (** p<0.01, *** p<0.001), and 2-way ANOVA with Bonferroni Post-tests comparing pre-treatment protocols versus continuous treatments (## p<0.01).