LL37

LL37 is a 37-amino acid cationic amphipathic alpha-helical antimicrobial peptide constituting the C-terminal domain of the human cathelicidin precursor protein hCAP18 (human cationic antimicrobial protein 18). It is the only cathelicidin peptide expressed in humans and represents a critical first-line effector of innate immune defense against bacteria, fungi, viruses, and protozoa.

LL37 exerts antimicrobial activity primarily through membrane disruption — its amphipathic helix inserts into microbial lipid bilayers at an angle, inducing pore formation or membrane fragmentation through toroidal pore or carpet mechanisms. Beyond direct antimicrobial activity, LL37 modulates immune responses by binding to LPS (reducing endotoxin activity), activating TLR4, recruiting neutrophils and dendritic cells, promoting wound healing through keratinocyte migration, and inducing autophagy in infected cells. Research also examines its complex, context-dependent roles in cancer biology.

• Amphipathic helix antimicrobial membrane disruption mechanism studies
• LPS binding and endotoxin neutralization research
• TLR4 signaling and innate immune cell recruitment studies
• Keratinocyte migration, wound healing, and re-epithelialization research
• Antiviral activity and viral membrane disruption pharmacology
• LL37 in cancer biology: pro- and anti-tumor activity research

Dose levels referenced by the MVLabs peptide calculator, shown for research reference only:

Cathelicidin antimicrobial peptide studied for wound and immune pathways.

Research reference only — not dosing guidance for human use. Use the calculator for other vials or volumes.

Supplied as a lyophilized powder. Store at 2–8 °C on receipt; protect from heat, light and moisture, and avoid excessive agitation. If reconstitution is required for laboratory work, use sterile technique — bacteriostatic water, or 0.6% acetic acid for low-solubility peptides. Protocols vary by research application.