LL-37 (5 mg) is a synthetic peptide, the biologically active fragment of the human cathelicidin precursor protein hCAP-18. It is naturally produced by immune and epithelial cells, including neutrophils, macrophages, and keratinocytes. This 37-amino-acid peptide has a cationic, amphipathic structure, enabling it to interact with cell membranes and microbial surfaces.

LL-37 research has focused on its role in innate immunity, antimicrobial activity, and regulation of inflammatory and cellular responses in experimental models. It is supplied as a high-purity, lyophilized powder in a single vial for reconstitution and use in controlled laboratory experiments.

LL-37 (5mg) Key Features & Specs

• Subcategory: Immune & Thymic Peptides
• CAS: 597562-32-8
• Chemical Formula: C₂₀₅H₃₄₀N₆₀O₅₃
• Molecular Weight: 4493.3 g/mol
• Peptide Sequence: Leu-Leu-Gln-Asp-Phe-Phe-Arg-Asn-Lys-Ser-Lys-Lys-Ile-Gln-Gly-Glu-Lys-Leu-Lys-Lys-Asp-Arg-Ile-Arg-Asn-Thr-Ala-Ile-Arg-Asn-Leu-Ile-Gly-Arg-Ile-Ala-Leu
• Synonyms: Cathelicidin, ropocamptide, Bac4, Cathelicidin antimicrobial peptide 18

For laboratory research use only.

LL-37 (5mg) Research Uses

LL-37 is studied as a key component of the innate immune system. It has been studied for its role in the innate immune response by interacting with microbial surfaces and coordinating experimental immune models.

LL-37 has been investigated for:

• Antimicrobial Activity: Disrupting bacterial, fungal, and viral membranes, including activity against gram-positive and gram-negative organisms and enveloped viruses.
• Biofilm Interaction: Its potential to disrupt biofilms and promote biofilm disruption.
• Immune Modulation: Its role in recruiting immune cells, such as neutrophils and macrophages, and influencing cytokine release.
• Inflammatory Signaling: Regulating pro- and anti-inflammatory pathways depending on cellular context.
• Tissue and Epithelial Response: Involvement in wound healing, epithelial migration, and angiogenesis.

Research also explores its interactions with nucleic acids and its role in autoimmune and inflammatory disease models. All applications remain within experimental settings.

LL-37 (5mg) Insights & Observed Findings

All reported data are derived from experimental systems and should not be interpreted as evidence of clinical effects.

Preclinical and in-vitro studies have used a range of concentrations to evaluate LL-37’s biological activity:

• 8–8 µM affects fungal organisms like Candida albicans.
• 10–100 µM concentrations are commonly used in biofilm disruption studies with Pseudomonas aeruginosa.
• 25 µg/mL (~5.6 µM) has been studied in epithelial models for antiviral effects.

In animal models:

• Topical concentrations around 2.5 mg/mL have been used in biofilm-associated infections.
• Systemic administration in neonatal studies involved doses around 100 µg/kg.
• In immune signaling studies, concentrations of 1–10 µM have been used to examine chemokine production and adhesion molecule expression.

LL-37 modulates inflammatory mediators such as IL-1β and IL-18 in immune cell models. Higher concentrations may affect cell viability depending on the cell type and experimental conditions.

Additional observations include:

• Modulation of reactive oxygen species and cellular stress responses.
• Changes in endothelial activation and vascular-related signaling.
• Interaction with lipopolysaccharides (LPS) in endotoxin-related studies.

These findings are context-specific and guide further research into host defense peptides and immune regulation.

LL-37 (5mg) Handling & Storage

• Store the lyophilized peptide at –20°C or below in a tightly sealed vial. Protect from light and moisture.
• Allow the vial to reach room temperature before opening to reduce condensation.
• Reconstituted solutions should be stored at 2–8°C for experimental use.
• For extended use, aliquoting is recommended to minimize repeated freeze–thaw cycles.
• All handling procedures should follow laboratory best practices and be validated according to the specific research protocol.

Compliance Notice: This product is intended for laboratory research use only and is not approved for human or veterinary use. It is not intended for diagnostic, therapeutic, or clinical applications. Any reference to biological activity or potential effects is based solely on preclinical or in-vitro findings and should not be interpreted as validated clinical outcomes. Researchers are responsible for ensuring proper handling, storage, and disposal in accordance with institutional, federal, and international guidelines.

References

1. Findlay EG, Currie AJ, Zhang A, et al. Exposure to the antimicrobial peptide LL-37 produces dendritic cells optimized for immunotherapy. OncoImmunology. 2019;8(8):1608106. doi:10.1080/2162402x.2019.1608106
2. Edfeldt K, Agerberth B, Rottenberg ME, et al. Involvement of the antimicrobial peptide LL-37 in human atherosclerosis. Arteriosclerosis Thrombosis and Vascular Biology. 2006;26(7):1551-1557. doi:10.1161/01.atv.0000223901.08459.57
3. Noore J, Noore A, Li B. Cationic Antimicrobial Peptide LL-37 Is Effective against both Extra- and Intracellular Staphylococcus aureus. Antimicrobial Agents and Chemotherapy. 2012;57(3):1283-1290. doi:10.1128/aac.01650-12
4. Chennupati SK, Chiu AG, Tamashiro E, et al. Effects of an LL-37-Derived antimicrobial peptide in an animal model of biofilm pseudomonas sinusitis. American Journal of Rhinology and Allergy. 2009;23(1):46-51. doi:10.2500/ajra.2009.23.3261
5. Aloul KM, Nielsen JE, Defensor EB, et al. Upregulating human cathelicidin antimicrobial peptide LL-37 expression may prevent severe COVID-19 inflammatory responses and reduce microthrombosis. Frontiers in Immunology. 2022;13:880961. doi:10.3389/fimmu.2022.880961
6. Kahlenberg JM, Kaplan MJ. Little peptide, big effects: The role of LL-37 in inflammation and autoimmune disease. The Journal of Immunology. 2013;191(10):4895-4901. doi:10.4049/jimmunol.1302005