Cathelicidin
A family of antimicrobial peptides found in humans and other mammals. LL-37 is the primary human cathelicidin, with broad-spectrum antimicrobial and immunomodulatory activity. Cathelicidins are studied as templates for novel antimicrobial peptide drug development.
Technical Context
LL-37 (37 amino acids beginning with Leu-Leu) is the only human cathelicidin, cleaved from the precursor protein hCAP-18 by proteinase 3. LL-37 has: broad-spectrum antimicrobial activity (gram-positive and gram-negative bacteria, fungi, viruses — through membrane disruption), anti-biofilm activity (disrupting bacterial biofilms at sub-antimicrobial concentrations), wound healing promotion (stimulating re-epithelialisation and angiogenesis), and immunomodulatory effects (modulating cytokine production, promoting chemotaxis, and enhancing phagocytosis). Vitamin D upregulates hCAP-18/LL-37 expression, linking vitamin D deficiency to increased infection susceptibility. Therapeutic applications under investigation: topical LL-37 for chronic wounds and diabetic ulcers (Phase I/II trials), LL-37 derivatives with improved selectivity and reduced haemolytic activity, and LL-37-based anti-biofilm strategies for device-related infections.