LL-37, the only cathelicidin peptide humans produce, acts as a natural antibiotic while also modulating immune responses across the lungs, gut, skin, and immune system — making it a promising drug candidate.
The only human cathelicidinWhile many species produce multiple cathelicidins, humans make just one — LL-37 — yet it performs antimicrobial, chemotactic, and immunomodulatory functions across at least four major body systems.
What the researchers found
This review establishes LL-37 as far more than an antimicrobial peptide. As the sole human cathelicidin, LL-37 serves as a broad-spectrum natural antibiotic, but also has potent chemotactic properties (attracting immune cells to sites of infection) and immunomodulatory effects. The authors analyzed LL-37’s therapeutic potential across four major systems: immune, respiratory, gastrointestinal, and skin — identifying specific molecular pathways and disease connections in each.
Why it matters
LL-37 is unique in human biology as the only cathelicidin we produce, yet it wears many hats — antimicrobial, immune signaling, wound healing, and inflammation modulation. This review maps those diverse functions to specific diseases and molecular pathways, making a comprehensive case for developing LL-37-based therapeutics that could address conditions ranging from infections to inflammatory bowel disease to skin disorders.
The numbers in context
4 body systems reviewed (immune, respiratory, GI, skin) · sole human cathelicidin · broad-spectrum antimicrobial activity
How the study worked
Comprehensive literature review analyzing published research on LL-37’s molecular mechanisms, biological activities, and therapeutic potential across immune, respiratory, gastrointestinal, and skin systems. No original experimental data were generated.
Who was studied
Not applicable — literature review
What this study cannot tell us
This is a narrative review without new experimental data. The therapeutic potential discussed remains largely preclinical, and the gap between LL-37’s known biology and its clinical development as a drug is not fully addressed. The review does not systematically assess evidence quality.
How to read the evidence
Rated expert opinion because this is a narrative review that synthesizes existing research without generating new data. It provides a comprehensive overview of LL-37 biology but does not systematically assess evidence quality.
When this study was published
Published in 2016 in Pharmacological Reports. LL-37 research has continued to expand significantly since this review, but it remains a useful overview of the peptide’s diverse biological roles and therapeutic potential.
The bigger picture
Antimicrobial peptides are increasingly seen as the next generation of antibiotics as drug resistance grows. LL-37 stands out because it’s already part of human innate immunity — we know it’s tolerated and functional. Understanding its full range of activities, from killing bacteria to modulating immune responses in the gut and lungs, positions it as one of the most therapeutically interesting natural peptides in the human body.
Questions still open
- Which of LL-37’s multiple functions — antimicrobial, immunomodulatory, or wound healing — is most feasible to exploit therapeutically?
- Can LL-37 or its derivatives be developed into drugs that maintain its diverse activities without triggering excessive inflammation?
- How do LL-37 levels change in specific disease states, and could it serve as a biomarker as well as a therapeutic?
Common questions
What makes LL-37 different from other antimicrobial peptides?
Is LL-37 being developed as a drug?
Read the original research
LL-37: Cathelicidin-related antimicrobial peptide with pleiotropic activity.
Pharmacological reports : PR, 68(4), 802-8
Citation
Fabisiak, Adam; Murawska, Natalia; Fichna, Jakub. (2016). LL-37: Cathelicidin-related antimicrobial peptide with pleiotropic activity.. Pharmacological reports : PR, 68(4), 802-8. https://doi.org/10.1016/j.pharep.2016.03.015