@article{mbs:/content/journal/jgv/10.1099/vir.0.045013-0, author = "Tripathi, Shweta and Tecle, Tesfaldet and Verma, Anamika and Crouch, Erika and White, Mitchell and Hartshorn, Kevan L.", title = "The human cathelicidin LL-37 inhibits influenza A viruses through a mechanism distinct from that of surfactant protein D or defensins", journal= "Journal of General Virology", year = "2013", volume = "94", number = "1", pages = "40-49", doi = "https://doi.org/10.1099/vir.0.045013-0", url = "https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.045013-0", publisher = "Microbiology Society", issn = "1465-2099", type = "Journal Article", abstract = "LL-37, the only human cathelicidin, is a cationic antimicrobial peptide with antibacterial and antifungal activity. LL-37 is released from neutrophil granules and produced by epithelial cells. It has been implicated in host defence against influenza A virus (IAV) in recent studies. We now demonstrate dose-related neutralizing activity of LL-37 against several seasonal and mouse-adapted IAV strains. The ability of LL-37 to inhibit these IAV strains resulted mainly from direct effects on the virus, since pre-incubation of virus with LL-37 was needed for optimal inhibition. LL-37 bound high-density lipoprotein (HDL), and pre-incubation of LL-37 with human serum or HDL reduced its antiviral activity. LL-37 did not inhibit viral association with epithelial cells as assessed by quantitative RT-PCR or confocal microscopy. This finding contrasted with results obtained with surfactant protein D (SP-D). Unlike collectins or human neutrophil defensins (HNPs), LL-37 did not induce viral aggregation under electron microscopy. In the electron microscopy studies, LL-37 appeared to cause disruption of viral membranes. LL-37 had additive antiviral activity when combined with other innate inhibitors like SP-D, surfactant protein A and HNPs. Unlike HNPs, LL-37 did not bind SP-D significantly. These findings indicate that LL-37 contributes to host defence against IAV through a mechanism distinct from that of SP-D and HNPs.", }