LL-37, Human

LL-37, human | antimicrobial peptide| Science-Peptide

【Properties】White or off-white powder
【Purity】≥95%
【Package】5mg, 10mg
【Storage】2-8℃, Storage -20℃, sealed storage
【More Information] Peptide price, sequence information, chemical structure, molecular weight, scientific research literature, please email inquiry

 

LL-37, human is a mature active peptide produced by proteolytic cleavage of hCAP18, a cathelicidin precursor of human origin, containing 37 amino acids, with a cationic amphiphilic α-helical structure, and is the only antimicrobial peptide of the cathelicidin family in the human body. It is the only cathelicidin family antimicrobial peptide in the human body. It is produced by neutrophils and epithelial cells (including cornea and conjunctiva), and is an important component of innate immunity. This product is a chemically synthesized high-purity catalog peptide for scientific research only, and is suitable for basic and translational research in the fields of antimicrobial mechanism, host immunity, corneal protection, wound healing, inflammation and tumor.

LL-37 has broad-spectrum antimicrobial activity.A systematic review published in Infect Genet Evol in 2025 (covering data up to March 2025) showed that LL-37 significantly inhibited more than 38 bacterial, 16 fungal, and 16 viral species, including Staphylococcus aureus (including MRSA), Pseudomonas aeruginosa, Escherichia coli, and several enveloped viruses [ Neshani et al., 2025]. The antimicrobial mechanism involves: (i) binding to bacterial anionic membrane, forming pores leading to cytoplasmic leakage; (ii) inhibiting and destroying biofilm (MRSA and P. aeruginosa biofilms were cleared within 30 min at low microgram concentrations); (iii) neutralizing LPS/LTA endotoxin; and (iv) inducing bacterial oxidative stress.

LL-37, human is a key factor in the natural immunity of the human cornea.Huang et al. found that LL-37 was distributed throughout the corneal epithelium; the expression of LL-37 was significantly up-regulated in the regenerating epithelium 24-48 h after trauma (Invest Ophthalmol Vis Sci, 2006). Under physiological conditions (containing NaCl and human tear fluid), LL-37 effectively killed ocular pathogens such as Pseudomonas aeruginosa with an EC₅₀ = 10.3 ± 2.5 μg/mL. LL-37 induced the migration of human corneal epithelial cells (HCECs) through the receptor FPRL1, and promoted the migration of IL LL-37 induced human corneal epithelial cell (HCEC) migration through the receptor FPRL1, and promoted the secretion of cytokines such as IL-8 and IL-6 (2-23-fold increase), but did not promote cell proliferation; high concentrations (>10 μg/mL) were cytotoxic. Therefore, the high expression of LL-37 in corneal regenerative epithelium has the dual functions of direct antibacterial and wound healing regulation.

Heterotrimeric peptides based on LL-37 have also demonstrated therapeutic potential for corneal infections.Ting et al. heterotrimerized LL-37 with human β-defensin 2 to obtain the HyHDP candidate peptide HDP56, which showed a low MIC against MRSA, Pseudomonas aeruginosa, and Fusarium solanacearum in the range of 3.1-6.3 µm/mL; 0.5 mg/mL HDP56 resulted in 93% bacterial reduction and comparable efficacy to levofloxacin (5 mg/mL) within 15 generations in a mouse model of MRSA keratitis. In a mouse model of MRSA keratitis, 0.5 mg/mL HDP56 resulted in a 93% reduction in bacteria, comparable to levofloxacin (5 mg/mL), and did not result in resistance within 15 generations (BMJ Open Ophthalmol, 2023).

LL-37 is involved in all phases of skin wound healing: promoting platelet activation and thrombosis (hemostatic phase); recruiting immune cells and promoting keratinocyte migration (inflammatory phase); up-regulating VEGF to promote angiogenesis and support fibroblast migration (proliferative phase); and regulating collagen synthesis and ECM remodeling to reduce scarring (remodeling phase) [J Funct Biomater, 2025]. In terms of delivery systems, PLGA nanoparticles or keratin hydrogels encapsulating LL-37 significantly promoted whole skin wound healing. A randomized double-blind controlled trial (NCT04098562) published in 2023 showed that LL-37 cream was significantly superior to placebo in terms of granulation tissue proliferation index at days 7, 14, 21, and 28 in patients with mild to moderately infected diabetic foot ulcers (p-values of 0.031, 0.009, 0.006, and 0.037, respectively) [Suwarsa et al. Arch Dermatol Res, 2023].

Immunomodulation: LL-37 has both pro-inflammatory and anti-inflammatory effects by chemotaxis of neutrophils and monocytes through FPRL1, EGFR and other receptors, and regulation of NF-κB and p38 MAPK signaling.

Anti-tumor: LL-37 engineered derivatives (e.g., 17BIPHE2) have selective anti-cancer activity while retaining antimicrobial activity.

Antiviral: Destroys the envelope of enveloped viruses (HIV-1, RSV, etc.) and inhibits viral entry and replication.

Cardiovascular and metabolic diseases: involved in atherosclerosis, thrombosis, cardiac hypertrophy, and obesity-associated adipose inflammation regulation; negatively correlated with HDL cholesterol.

Autoimmune diseases and amyloidosis: role in SLE, impaired degradation of NETs and anti-amyloidogenesis.

More modification strategies (truncation, reverse analogs) and nanodelivery systems could extend half-life and reduce cytotoxicity [Int J Mol Sci, 2025].

Store the lyophilized powder at -20°C, avoid repeated freezing and thawing; dissolve and dispense at -80°C for long term storage.

Neshani A, et al. Decoding LL-37: Structure and antimicrobial mechanisms against microbial threats. Infect Genet Evol. 2025;136:105853.

Huang LC, et al. Multifunctional roles of human cathelicidin (LL-37) at the ocular surface. Invest Ophthalmol Vis Sci. 2006;47(6):2369-2380.

Ting DSJ, et al. OP-4 Development of novel human-derived hybrid host defense peptides for infectious keratitis. BMJ Open Ophthalmol. 2023;8(Suppl 1):A2.1.

Multiple biological functions of skin-derived AMPs during the wound-healing process. J Funct Biomater. 2025;16(5):174.

Suwarsa O, et al. Efficacy of LL-37 cream in enhancing healing of diabetic foot ulcer: a randomized double-blind controlled trial. Arch Dermatol Res. 2023;315(9):2623-2633.

Voronko OE, et al. Antimicrobial peptides of the cathelicidin family: Focus on LL-37 and its modifications. Int J Mol Sci. 2025;26(16):8103.