Cathelicidin antimicrobial peptide 18

LL-37, also known as CAP-18 for Cathelicidin antimicrobial peptide 18, is a 37 amino acid cationic peptide. LL-37 is also a typical linear antimicrobial peptide which can eliminate a wide range of pathogenes, including bacteria, viruses, fungi, and parasites. LL-37 is the only human cathelicidin peptide reported yet, found in lysosomes of macrophages and leukocytes. LL-37 plays an important role in the first act of defense against local infection and systemic invasion of pathogens at sites of inflammation. LL-37 shows cytotoxicity against bacterial and normal eukaryotic cells and is significantly resistant to proteolytic degradation. Besides its antimicrobial functions, LL-37 also has immunomodulatory roles. LL-37 suppresses the production of pro-inflammatory cytokines, TNF-α and IL-6 in infected monocytes. LL-37 increases cytokine and chemokine liberation from local cells and leucocytes and has chemotactic effects on a large number of immune cells.