Premium Nahrungsergänzungsmittel | artgerecht

LL-37 – Antimicrobial Peptide and Innate Immunity

LL-37 is an endogenous antimicrobial peptide of the cathelicidin family that plays a central role in innate immunity and possesses immunomodulatory and anti-inflammatory properties.

Regular tips about health Regular tips about health

Things worth knowing about "LL-37"

LL-37 is an endogenous antimicrobial peptide of the cathelicidin family that plays a central role in innate immunity and possesses immunomodulatory and anti-inflammatory properties.

What is LL-37?

LL-37 is an antimicrobial peptide (AMP) and the only known human member of the cathelicidin family. It is derived from the precursor protein hCAP-18 (human cationic antimicrobial protein 18) and consists of 37 amino acids. The name LL-37 reflects its structure: the first two amino acids are both leucine (L), followed by 35 additional residues. LL-37 is produced by a variety of cell types, including neutrophils, keratinocytes, airway and intestinal epithelial cells, and macrophages.

Biological Functions

LL-37 serves multiple essential roles in the human body:

Antimicrobial activity: LL-37 directly kills bacteria, viruses, fungi, and certain parasites. It binds to the negatively charged membranes of microorganisms, disrupts their membrane integrity, and causes cell death.
Immunomodulation: The peptide regulates inflammatory responses by influencing the activation of immune cells such as monocytes, dendritic cells, and T cells.
Wound healing: LL-37 promotes the migration and proliferation of epithelial cells, supporting tissue repair and wound closure.
Angiogenesis: It stimulates the formation of new blood vessels, which is important for tissue regeneration.
Endotoxin neutralization: LL-37 binds and neutralizes bacterial lipopolysaccharides (LPS), preventing excessive immune responses such as septic shock.

Production and Regulation

The production of LL-37 in the body is regulated by several factors. Vitamin D plays a particularly important role by stimulating the expression of the CAMP gene (Cathelicidin Antimicrobial Peptide), which encodes LL-37. Additional factors influencing LL-37 production include:

Infections and inflammatory stimuli
Certain fatty acids (e.g., short-chain fatty acids from the gut microbiome)
Cytokines and growth factors
Skin irritation and mechanical stimuli

LL-37 and Disease

Conditions Associated with Reduced LL-37 Activity

A deficiency or reduced activity of LL-37 is associated with increased susceptibility to infections and certain diseases:

Atopic dermatitis (eczema): Patients with eczema often show reduced LL-37 levels in the skin, which helps explain their heightened susceptibility to bacterial superinfections, particularly with Staphylococcus aureus.
Crohn's disease: Reduced LL-37 expression in the intestinal mucosa may contribute to impaired immune defense in the gut.
Recurrent infections: Particularly of the respiratory tract and skin.

Conditions Associated with Elevated LL-37 Activity

Conversely, excessive LL-37 production can also be harmful:

Psoriasis: Elevated LL-37 levels activate dendritic cells and promote the chronic skin inflammation characteristic of psoriasis.
Systemic lupus erythematosus (SLE): LL-37 can combine with self-DNA to misdirect the immune system, contributing to autoimmune reactions.
Rosacea: Increased LL-37 activity in the skin is implicated in the development of rosacea.

Therapeutic Potential

Due to its diverse properties, LL-37 is an intensively researched compound in biomedical science. Potential therapeutic applications include:

Development of new antibiotics and anti-infective agents, especially against multidrug-resistant pathogens
Improvement of wound healing, for example in chronic wounds and diabetic foot ulcers
Treatment of skin conditions such as atopic dermatitis
Cancer research: LL-37 exhibits both tumor-promoting and tumor-suppressive properties depending on the cancer type
Use as an adjuvant in vaccines to enhance immune responses

Diagnostic Relevance

Measurement of LL-37 levels in blood, stool, saliva, or skin tissue can serve as a biomarker in research and clinical settings to assess inflammatory status, innate immune defense capacity, or therapeutic response. However, standardized routine clinical assays are still under development.

References

Vandamme D, Landuyt B, Luyten W, Schoofs L. A comprehensive summary of LL-37, the factotum human cathelicidin peptide. Cellular Immunology, 2012; 280(1): 22-35.
Mookherjee N, Anderson MA, Haagsman HP, Davidson DJ. Antimicrobial host defence peptides: functions and clinical potential. Nature Reviews Drug Discovery, 2020; 19(5): 311-332.
Tecle T, Tripathi S, Hartshorn KL. Review: Defensins and cathelicidins in lung immunity. Innate Immunity, 2010; 16(3): 151-159.

Building Blocks for a Healthy Life

As an integrated manufacturer, we develop & produce evidence-based, patented, and non-patented formulations. We work exclusively with plant and natural extracts according to the strictest purity & quality standards.
The combination of science & modern technology with the laws of nature creates solutions consistently tailored to humans – for the highest good: health.