🛡️LL-37 (Cathelicidin)

What Is LL-37?

LL-37 is the only member of the cathelicidin family expressed in humans, derived from the C-terminal region of the precursor protein hCAP18. Produced by neutrophils, epithelial cells, and keratinocytes, it serves as a first-line antimicrobial defence and key wound healing mediator.

Key Mechanisms

• Membrane disruption — electrostatic interaction with bacterial membranes; kills broad-spectrum Gram+ and Gram− bacteria
• Anti-biofilm — disrupts established biofilms at sub-MIC concentrations
• FPRL-1 receptor signalling — induces angiogenesis, cell migration and wound closure
• Innate immune modulation — reduces LPS-driven TLR4 activation; prevents endotoxic shock
• Antiviral activity — inhibits HIV, influenza, HSV envelope fusion

Key References

1. Vandamme D et al. "A comprehensive summary of LL-37, the factotum human cathelicidin peptide." Cell Immunol, 2012;280:22–35.
2. Ramos R et al. "Wound healing activity of LL-37 is abrogated by DHP-2." Biochimie, 2011;93(2):234–238.