Antiviral Activity and Increased Host Defense against Influenza Infection Elicited by the Human Cathelicidin LL-37
Figure 1
LL-37 Protects Mice Against Influenza Virus Disease.
(A,B) Groups of 5 mice were inoculated with 10 MLD50 of A/Puerto Rico/8/1934 influenza virus by the intranasal route on day 0. Mice were nebulized with 200 µl of saline (control), zanamivir (500 µg/ml), LL-37 peptide (500 µg/ml) or scrambled LL-37 control peptide (500 µg/ml) once daily from day -1 to day 7. Mouse body weight (A) and survival (B) was monitored daily up to 14 days post infection. Data represent mean values ± SEM, for three independent experiments. Statistical analysis was performed using Kaplan Meier with a Mantel-Cox (log rank) test. Survival curves obtained with Zanamivir and LL-37 treatments were significantly different (P≤0.001) compared to saline control treatment. There was no difference between saline treated and sLL-37 treated groups. (C) Groups of three mice (Female, 6–8 week old Balb/c) were inoculated with 10 MLD50 of A/PR/8/34 virus intranasally on day 0. Mice were nebulized with 200 µl of saline (control) zanamivir (500 µg/ml), LL-37 peptide (500 µg/ml) or scrambled LL-37 control peptide (500 µg/ml) once daily from day -1 to day 2. Mice were euthanized on day 3 and viral titer in the lungs was assessed by plaque assay. Figure is representative of three independent experiments. Figure shows mean values ± SEM. Statistical analysis was performed using a Student t-test to compare virus infected animals with virus/peptide and virus/zanamivir treated animals (*P≤0.05).