LL-37
Human ResearchLL-37
The only human cathelicidin antimicrobial peptide. Researched for its broad-spectrum antimicrobial effects, wound healing, and immune modulation.
Dose
Varies significantly by application method and research context, ranging from micrograms to milligrams.
Route
Topical, SubQ injection
Cycle
Highly variable depending on the research indication, from acute treatment for a few days to chronic applications over weeks.
Storage
2-8°C (refrigerated) for up to 2 years, protected from light.
What is LL-37?
LL-37 is the sole human cathelicidin antimicrobial peptide, a key component of the innate immune system. Research extensively explores its broad-spectrum antimicrobial activity against bacteria, fungi, and viruses, primarily through disruption of microbial cell membranes. Beyond its direct microbicidal effects, LL-37 is also studied for its significant roles in immune modulation, including chemotaxis of immune cells, cytokine and chemokine regulation, and promotion of angiogenesis and re-epithelialization in wound healing. Its ability to disrupt bacterial biofilms and exert anti-inflammatory effects at certain concentrations makes it a subject of considerable interest in developing novel therapeutic strategies for various infections and inflammatory conditions.
Key Benefits
- Broad-spectrum antimicrobial activity
- Wound healing
- Biofilm disruption
- Immune modulation
- Anti-inflammatory at low doses
Mechanism of Action
- Disrupts microbial cell membranes
- Modulates TLR signaling
- Promotes wound healing
- Stimulates immune cell recruitment
Best For
- Antimicrobial research
- Wound healing research
- Immune research
Body Systems
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Molecular Information
Molecular weight
4493.2 Da
Length
37 amino acids
Type
Cathelicidin Antimicrobial Peptide
Amino acid sequence
LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Leucine-Leucine-Glycine-Aspartic Acid-Phenylalanine-Phenylalanine-Arginine-Lysine-Serine-Lysine-Glutamic Acid-Lysine-Isoleucine-Glycine-Lysine-Glutamic Acid-Phenylalanine-Lysine-Arginine-Isoleucine-Valine-Glutamine-Arginine-Isoleucine-Lysine-Aspartic Acid-Phenylalanine-Leucine-Arginine-Arginine-Leucine-Valine-Proline-Arginine-Threonine-Glutamic Acid-Serine
Research Indications
Broad-spectrum activity against bacteria, fungi, and viruses
Research indicates potent direct antimicrobial effects by disrupting microbial membranes, effective against a wide range of pathogens including antibiotic-resistant strains.
Biofilm disruption and prevention
Studies show LL-37's ability to inhibit biofilm formation and disrupt established biofilms, which is crucial for managing chronic infections.
Research Protocols
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Topical application for chronic wound infection | 50-200 µg/cm² of wound surface area | Once daily or twice daily | Topical |
| Subcutaneous administration for systemic immune modulation | 0.1-0.5 mg/kg | Daily or every other day | Subcutaneous |
| In vitro testing for antimicrobial activity | Range from 0.1 to 10 µM (or mg/L) | Single exposure for MIC determination | In vitro culture |
| Topical application for skin infections | 0.5-1% solution or cream | Twice daily | Topical |
| In vivo study for anti-biofilm effect | 1-5 mg/kg | Once daily | Local injection or sustained release |
Research protocols for LL-37 vary widely based on the specific condition being investigated, the administration route (topical vs. subcutaneous), and the desired outcome. Dosing and frequency should strictly adhere to established research guidelines.
Peptide Interactions
- Monitor Combination
Corticosteroids
Corticosteroids are immunosuppressive and may theoretically counteract some of LL-37's immune-boosting effects, particularly in wound healing or infection contexts. However, they might also synergize in reducing excessive inflammation.
- Synergistic
Antibiotics
Research suggests LL-37 can act synergistically with conventional antibiotics, potentially enhancing their efficacy and overcoming antibiotic resistance, especially against biofilms.
- Use Caution
Other immunomodulators
Combining LL-37 with other compounds that significantly alter immune responses requires careful monitoring due to the potential for complex and unpredictable interactions.
- Monitor Combination
Pro-inflammatory cytokines (e.g., TNF-α, IL-1β)
LL-37 can modulate cytokine production; interactions with exogenous cytokines may alter the overall inflammatory state. Doses may need careful consideration.
- Compatible
Anticoagulants
No direct evidence of significant interactions with anticoagulants has been widely reported. However, as with any systemic agent, monitoring in susceptible individuals is prudent.
How to Reconstitute
- 1Carefully remove the cap from the lyophilized LL-37 vial.
- 2Swab the rubber stopper with an alcohol wipe and allow it to air dry.
- 3Using a sterile syringe, draw up the desired amount of sterile reconstituting solution (e.g., BWFI or SWFI).
- 4Slowly inject the reconstituting solution into the vial, aiming the stream at the glass side, not directly onto the powder.
- 5Gently swirl the vial (do not shake vigorously) until the powder is completely dissolved. This may take several minutes.
- 6Once dissolved, the solution should be clear and colorless. If particles are present or the solution is cloudy, do not use.
Sterile bacteriostatic water for injection (BWFI) or sterile water for injection (SWFI) are commonly used. The final concentration should be determined by the specific research protocol.
What to Expect
- Within days (topical): For wound healing applications, initial signs of improved wound bed appearance or reduced bacterial load may be observed.
- Week 1-2 (topical/subcutaneous): Continued progress in wound repair; potential reduction in local inflammation or infection markers.
- Week 2-4 (subcutaneous/systemic effects): Immunomodulatory effects may become more evident, potentially influencing systemic inflammatory responses or pathogen clearance.
- Beyond 4 weeks: For chronic conditions, sustained application might be investigated for long-term immune support, anti-biofilm activity, or management of persistent infections.
- Highly variable: Due to the diverse research applications and mechanisms of action, the timeframe for observable effects can vary greatly.
Side Effects & Safety
| Effect | Frequency | Severity |
|---|---|---|
| Skin irritation (topical) | Common | Mild |
| Pain at injection site | Common | Mild |
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Open CalculatorPeptides discussed here are for research purposes only. Nothing on this page is medical advice. Always consult a qualified professional before making health decisions.