Quick Facts

Chemical Name
Cathelicidin Antimicrobial Peptide
Also Known As
Cathelicidin, hCAP18
Category
Immune & Antimicrobial
Administration
Primarily a research peptide

What is LL-37?

LL-37 is a 37-amino acid peptide that represents the active form of the human cathelicidin hCAP18. It is produced by various cells including neutrophils, epithelial cells, and macrophages. As part of the innate immune system, LL-37 has direct antimicrobial activity against bacteria, viruses, and fungi. Beyond its antimicrobial role, it also modulates inflammation, promotes wound healing, and influences adaptive immunity.

How Does LL-37 Work?

LL-37 has multiple mechanisms of action. As an antimicrobial, it disrupts microbial membranes through its cationic and amphipathic nature. It binds to and neutralizes bacterial endotoxins (LPS), reducing inflammation. LL-37 also acts as a chemokine, recruiting immune cells to sites of infection. Additionally, it promotes angiogenesis and wound healing through effects on endothelial cells and fibroblasts. The peptide can also modulate inflammatory responses, both pro and anti-inflammatory depending on context.

Research-Backed Benefits

Antimicrobial Activity

Strong Evidence

Directly kills bacteria, viruses, and fungi through membrane disruption.

Wound Healing

Moderate Evidence

Promotes tissue repair through effects on cell migration and angiogenesis.

Anti-Biofilm Effects

Moderate Evidence

Can disrupt bacterial biofilms that are resistant to conventional antibiotics.

Inflammation Modulation

Moderate Evidence

Regulates inflammatory responses and neutralizes bacterial toxins.

Immune Recruitment

Strong Evidence

Attracts immune cells to sites of infection or injury.

Dosage Guidelines

Disclaimer: This content is for educational purposes only. Peptides are research compounds not approved by the FDA for human use. Always consult with a qualified healthcare provider.

Typical Range
Research protocols vary widely
Frequency
Depends on application
Duration
Varies by use case

LL-37 is primarily used in research settings. Topical and injectable forms have been studied.

Side Effects & Safety

  • Limited human safety data for exogenous administration
  • Potential for injection site reactions
  • May affect inflammation (context-dependent)
  • High doses may have unintended effects

Frequently Asked Questions

LL-37 is a natural antimicrobial peptide that kills pathogens, promotes wound healing, modulates inflammation, and recruits immune cells.
Yes, LL-37 is produced by various cells as part of the innate immune system. It's found in skin, respiratory tract, gut, and other tissues.
LL-37 can be effective against some antibiotic-resistant bacteria because it works through physical membrane disruption rather than the pathways that develop antibiotic resistance.

References

  1. Vandamme D, et al. "LL-37: Cathelicidin antimicrobial peptide." Cellular Immunology, 2012. PMID: 22421098

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