An antimicrobial peptide of the cathelicidin family that provides innate immune defense by killing pathogens and modulating inflammation and wound healing.
LL-37 is a natural peptide that can both help and hurt cancer growth depending on the tissue type. It can boost wound healing and immune cell movement, but in some cancers (like ovarian, lung, breast) it may actually promote tumor growth, while in others (like colon and gastric) it seems to fight cancer. Vitamin D can increase LL-37 levels in immune cells, which may improve the body’s anti‑cancer defenses.
Kany. Andreas M AM; Sikandar. Asfandyar A; Yahiaoui. Samir S; Haupenthal. Jörg J; Walter. Isabe...
Scientists made a new compound that blocks a bacterial enzyme (LasB) used by Pseudomonas aeruginosa to protect itself. By blocking this enzyme, the natural antimicrobial peptide LL‑37 works better, the bacteria form less sticky biofilm, and they release less DNA that helps them resist treatment. The compound is still experimental and not something you can buy or use at home.
Hemshekhar. Mahadevappa M; Choi. Ka-Yee Grace KG; Mookherjee. Neeloffer N
The study shows that the human peptide LL-37 can pull immune cells to a site (chemoattractant) by turning on a protein called Cdc42, but its ability to calm inflammation (by making IL-1RA) does not need Cdc42. In other words, Cdc42 acts like a switch that decides whether LL-37 acts like a rally‑call for immune cells or like a peace‑keeper.
Holásková. Edita E; Galuszka. Petr P; Mičúchová. Alžbeta A; Še...
Scientists figured out how to grow a human antimicrobial peptide called LL‑37 inside barley seeds. They tried different tag tricks to boost production, chose the best ones, and made several barley lines that safely produce the peptide at low levels (about 0.55 mg per kilogram of grain). The peptide can be released from its tags and still works, showing plants could be a cheap way to make LL‑37.
In older patients with sepsis, the blood level of the antimicrobial peptide LL‑37 is higher than in healthy people, but it drops as the illness gets worse. Lower LL‑37 levels are linked to higher scores on severity scales (APACHE II, SOFA) and to a higher chance of dying within 28 days. A cutoff around 1,283 µg/L can help predict who is at higher risk.
The study shows that the natural antimicrobial peptide LL‑37 (and the defensin hBD‑2) can boost the activity of mast cells by increasing the levels of certain immune sensors (NOD1, NOD2, RIG‑I) and making the cells release inflammatory chemicals and move more. This was seen in mouse peritoneal mast cells grown in a dish, not in people.
Wanmakok. Manlika M; Orrapin. Santhasiri S; Intorasoot. Amornrat A; Intorasoot. Sorasak S
Scientists made a new hybrid antimicrobial peptide (AL32-P113) by joining parts of human LL‑37 and histatin‑5, produced it in bacteria, and showed it kills a range of germs better than the original peptides. However, it also caused more damage to human red blood cells, indicating potential safety concerns.
Jiang. Jiang J; Chen. Shixuan S; Wang. Hongjun H; Carlson. Mark A MA; Gombart. Adrian F AF; Xie. Jin...
Scientists found a new way to puff up thin fiber mats into fluffy 3D structures using carbon dioxide. This process keeps the antibacterial peptide LL‑37 active and helps cells move into the material, grow new blood vessels, and trigger a healing immune response when implanted in rats.
Malekkhaiat Häffner. Sara S; Nyström. Lina L; Browning. Kathryn L KL; Mörck Nielsen....
Loading the antimicrobial peptide LL‑37 onto negatively‑charged Laponite clay particles makes the particles positively charged and causes them to stick together with Gram‑negative bacteria like E. coli, but it doesn’t kill the bugs by itself. Free LL‑37 can kill bacteria by punching holes in their membranes, while the LL‑37‑Laponite combo both clumps the bacteria and damages them. This clumping reduces the bacteria’s ability to trigger inflammation.
Di Virgilio. Francesco F; Giuliani. Anna L AL; Vultaggio-Poma. Valentina V; Falzoni. Simonetta S; Sa...
Scientists found that the immune‑related protein P2X7, which usually reacts to ATP, can also be turned on by other substances like the antimicrobial peptide LL‑37, the antibiotic polymyxin B, and some inflammation‑related proteins. How these non‑ATP molecules trigger the receptor is still unclear, but they may work together with ATP during inflammation or tumor growth.
Hernández-Villa. Laura L; Manrique-Moreno. Marcela M; Leidy. Chad C; Jemioła-Rzemiń...
The study shows that a bacterial lipid called cardiolipin can make the antimicrobial peptide LL‑37 less able to break open bacterial cells, even though LL‑37 still sticks to the bacteria. This means that some bacteria can protect themselves against LL‑37 by changing their membrane makeup.
Thomi. Rahel R; Schlapbach. Christoph C; Yawalkar. Nikhil N; Simon. Dagmar D; Yerly. Daniel D; Hunge...
The study shows that the antimicrobial peptide LL‑37 is higher in the skin of people with hidradenitis suppurativa, a painful inflammatory condition, and that it’s linked to immune cells and inflammatory signals. It also finds LL‑37 can make certain T‑cells multiply by raising calcium inside the cells, independent of other immune helpers. This suggests LL‑37 plays a role in driving inflammation, not just fighting microbes.
A short peptide from rice (AmyI-1-18) and a tweaked version called [N3L]AmyI-1-18 can make human blood‑vessel cells grow, form new blood‑vessel‑like structures, and move faster in lab dishes, similar to the human peptide LL‑37. This suggests they might help heal wounds, but the work is still only in cell cultures.
Scientists stuck a short piece of the human antimicrobial protein LL-37, called FK-16, onto titanium metal and found it kills a wide range of tough, drug‑resistant bacteria and stops them from sticking and forming biofilms. This works better than the full‑length LL-37 and is cheaper to make, but it’s a surface coating, not a pill you can take.
Mansbach. Jonathan M JM; Hasegawa. Kohei K; Ajami. Nadim J NJ; Petrosino. Joseph F JF; Piedra. Pedro...
In a big study of over a thousand babies with bronchiolitis, kids with the lowest blood levels of the immune peptide LL‑37 were almost twice as likely to need intensive care and stayed in the hospital longer. Low LL‑37 also showed a strong link to infection by RSV, the most common cause of bronchiolitis, while higher LL‑37 was tied to the less severe rhinovirus.
Kusaka. S S; Nishida. A A; Takahashi. K K; Bamba. S S; Yasui. H H; Kawahara. M M; Inatomi. O O; Sugi...
The study found that the natural antimicrobial peptide LL‑37 is produced at higher levels in the inflamed gut lining of ulcerative colitis and Crohn’s disease patients. In lab experiments, a viral‑mimic molecule (poly I:C) activated TLR‑3, which triggered a cascade (TRIF, TRAF6, TAK1, MAPKs, NF‑κB, AP‑1) that increased LL‑37 production in colonic cells, and the peptide then reduced inflammation caused by bacterial LPS.
Rozenbaum. René T RT; Su. Linzhu L; Umerska. Anita A; Eveillard. Matthieu M; Håkansson. Jo...
The research shows that putting the antimicrobial peptide LL‑37 onto monolaurin lipid nanocapsules does not improve fighting Staphylococcus aureus infections in real mice, even though it looked promising in lab dishes. In live animals, the combination didn’t speed wound healing and sometimes performed worse than a simple saline rinse.
Svensson. Daniel D; Lagerstedt. Jens O JO; Nilsson. Bengt-Olof BO; Del Giudice. Rita R
The study found that a blood protein called ApoA‑I, which is a major part of good‑cholesterol (HDL), sticks to the immune peptide LL‑37 and stops it from killing the cells that line blood vessels. When ApoA‑I is present, LL‑37 is less harmful, but if ApoA‑I levels are low, LL‑37 can damage those cells.
Researchers measured vitamin D levels and the immune peptide LL‑37 in Ethiopian people with active tuberculosis and in healthy controls. They found that vitamin D levels were low overall and similar between sick and healthy groups, and the amount of LL‑37 didn’t show a clear link to vitamin D status.
Lima. Stella Maris F SMF; Freire. Mirna S MS; Gomes. Ana Luisa O ALO; Cantuária. Ana Paula C AP...
The study tested the natural peptide LL‑37 against common root‑canal bugs and compared it to a standard dental disinfectant. LL‑37 killed the bacteria at a certain concentration and changed immune signals, showing it works better than the other peptides tested, but the research is limited to dental cells, not whole‑body use.