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LL-37

Cathelicidin, hCAP-18, FALL-39, CAP-18

An antimicrobial peptide of the cathelicidin family that provides innate immune defense by killing pathogens and modulating inflammation and wound healing.

Quick Stats
Studies 2230
Trials 95
Formula C205H340N60O53
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Utility 2
pubmed Jul 22, 2009

The cathelicidin LL-37 activates human mast cells and is degraded by mast cell tryptase: counter-regulation by CXCL4.

Schiemann. Florian F; Brandt. Ernst E; Gross. Roland R; Lindner. Buko B; Mittelstädt. Jessica J...

The study shows that the natural antimicrobial peptide LL‑37 can trigger mast cells to release their contents, which may cause inflammation, and that mast cells quickly break down LL‑37 so it loses its antimicrobial and anti‑LPS effects. A platelet protein called CXCL4 can protect LL‑37 from this breakdown, but it does so by messing with the mast cell enzyme rather than directly blocking it.

Utility 2
pubmed Jul 6, 2009

Secondary necrosis of apoptotic neutrophils induced by the human cathelicidin LL-37 is not proinflammatory to phagocytosing macrophages.

Li. Hsin-Ni HN; Barlow. Peter G PG; Bylund. Johan J; Mackellar. Annie A; Björstad. Ase A; Conlo...

The study shows that the human peptide LL‑37 can quickly turn dying neutrophils into a second‑stage dead form, but this doesn’t make the immune cells that eat them (macrophages) more inflamed. In fact, the usual calming effect of dying neutrophils on macrophages stays or even gets stronger. However, this process also spills out neutrophil granule chemicals that could be harmful if they build up.

Utility 2
pubmed Dec 30, 2009

LL-37 promotes rapid sensing of CpG oligodeoxynucleotides by B lymphocytes and plasmacytoid dendritic cells.

Hurtado. Plinio P; Peh. Chen Au CA

LL-37, a natural antimicrobial peptide, helps immune cells spot bacterial DNA (CpG motifs) much faster and with far less DNA needed. It works in blood and whole‑blood conditions, and it does this without needing its usual bactericidal shape. The effect is seen in B cells and special dendritic cells, but not in T cells, and it only works with bacterial‑type DNA, not human DNA.

Utility 2
pubmed Jul 6, 2009

Lipid segregation explains selective toxicity of a series of fragments derived from the human cathelicidin LL-37.

Epand. Raquel F RF; Wang. Guangshun G; Berno. Bob B; Epand. Richard M RM

Researchers looked at pieces of the human antimicrobial peptide LL-37 and found that some fragments can pull negatively charged lipids together in bacterial membranes. When they do this, they kill bacteria that have both negative and neutral lipids (like many gram‑negative bugs) but spare those that only have negative lipids. This explains why certain fragments only work against gram‑negative bacteria.

Utility 2
pubmed Nov 1, 2010

The antimicrobial peptide human cationic antimicrobial protein-18/cathelicidin LL-37 as a putative growth factor for malignant melanoma.

Kim. J E JE; Kim. H J HJ; Choi. J M JM; Lee. K H KH; Kim. T Y TY; Cho. B K BK; Jung. J Y JY; Chung....

The study found that the antimicrobial peptide LL‑37 is produced at high levels by melanoma cells and actually makes these skin cancer cells grow, move, and invade more, while it is low or absent in non‑cancerous skin lesions.

Utility 2
pubmed Apr 5, 2009

Association of human cathelicidin (hCAP-18/LL-37) gene expression with cardiovascular disease risk factors.

Benachour. H H; Zaiou. M M; Samara. A A; Herbeth. B B; Pfister. M M; Lambert. D D; Siest. G G; Visvi...

The study found that higher levels of the immune peptide LL‑37 in blood cells are linked to several heart‑risk factors like higher blood pressure, bad cholesterol, triglycerides, and blood sugar, especially in men, and to weight‑related measures in women. This suggests LL‑37 might be a marker of cardiovascular risk, but the research doesn’t tell us how to change LL‑37 levels or use it in a treatment plan yet.

Utility 2
pubmed Apr 17, 2009

Endotoxin, capsule, and bacterial attachment contribute to Neisseria meningitidis resistance to the human antimicrobial peptide LL-37.

Jones. Allison A; Geörg. Miriam M; Maudsdotter. Lisa L; Jonsson. Ann-Beth AB

The study shows that the bacteria causing meningitis can hide from the human antimicrobial peptide LL‑37 when they stick to our cells, and their outer coating (capsule) and endotoxin layer help block LL‑37 from reaching them. This means LL‑37 isn’t a magic bullet against these bugs, especially when they’re attached to tissues, and low doses might even make them tougher by boosting their capsule production.

Utility 2
pubmed Aug 14, 2008

Vitamin D3 induces pro-LL-37 expression in myeloid precursors from patients with severe congenital neutropenia.

Karlsson. Jenny J; Carlsson. Göran G; Larne. Olivia O; Andersson. Mats M; Pütsep. Katrin K

The study shows that the active form of vitamin D3 can turn on the gene for the antimicrobial peptide LL‑37 in immune‑cell precursors from patients with a rare neutropenia disorder, even though those cells normally don’t make it. This suggests vitamin D3 might boost innate immunity by increasing LL‑37, but the work was done in a very specific disease context and used the potent 1,25‑dihydroxy‑vitamin D3 form, not regular supplements.

Utility 2
pubmed Jan 28, 2009

Levels of innate immune factors in genital fluids: association of alpha defensins and LL-37 with genital infections and increased HIV acquisition.

Levinson. Pauline P; Kaul. Rupert R; Kimani. Joshua J; Ngugi. Elizabeth E; Moses. Stephen S; MacDona...

The study found that a natural protein called LL‑37, which can block HIV in lab tests, is actually higher in women with bacterial STIs and those who later got HIV, suggesting that more LL‑37 isn’t protective in real life.

Utility 2
pubmed May 12, 2009

The human host defense peptide LL-37 induces apoptosis in a calpain- and apoptosis-inducing factor-dependent manner involving Bax activity.

Mader. Jamie S JS; Mookherjee. Neeloffer N; Hancock. Robert E W RE; Bleackley. R Chris RC

LL-37, a natural antimicrobial peptide, can kill certain leukemia cells by triggering a form of programmed cell death that doesn’t rely on the usual caspase enzymes. Instead, it needs calcium, calpain enzymes, and a protein called AIF that moves from mitochondria to the nucleus, plus the Bax protein to get the mitochondria involved. This effect was seen in lab-grown Jurkat T‑cell lines, not in whole people.

Utility 2
pubmed Oct 26, 2008

FPRL1-mediated induction of superoxide in LL-37-stimulated IMR90 human fibroblast.

Iaccio. Annalisa A; Cattaneo. Fabio F; Mauro. Martina M; Ammendola. Rosario R

The study shows that the peptide LL‑37 can trigger a specific cell‑surface receptor (FPRL1) in human fibroblast cells, leading to a chain reaction that activates an enzyme complex (NADPH oxidase) and produces superoxide, a type of reactive oxygen species. This effect can be blocked by drugs that inhibit the receptor or downstream signals, confirming the pathway. For DIY health enthusiasts, it suggests that LL‑37 isn’t just antimicrobial—it can also raise oxidative stress in skin cells, which may have implications for aging and tissue health.

Utility 2
pubmed Dec 15, 2008

The host defense peptide LL-37 selectively permeabilizes apoptotic leukocytes.

Björstad. Ase A; Askarieh. Galia G; Brown. Kelly L KL; Christenson. Karin K; Forsman. Huamei H;...

LL-37 is a natural antimicrobial peptide that not only kills bacteria but also can poke holes in the membranes of dying immune cells (apoptotic leukocytes) while leaving healthy cells alone. This effect happens quickly, doesn’t need cell receptors, and can be blocked by components in blood like HDL. The finding hints that LL-37 might help clear out dead immune cells and influence inflammation, but it isn’t a ready‑to‑use supplement for everyday health hacks.

Utility 2
pubmed May 21, 2009

Low concentrations of LL-37 alter IL-8 production by keratinocytes and bronchial epithelial cells in response to proinflammatory stimuli.

Filewod. Niall C J NC; Pistolic. Jelena J; Hancock. Robert E W RE

Even at low, natural levels, the peptide LL-37 can boost the release of inflammation‑related chemicals (like IL‑8) from skin and airway cells when they’re also exposed to bacterial signals. This means LL-37 isn’t just a passive defender; it can amplify immune reactions in the lining of the body.

Utility 2
pubmed Dec 20, 2008

The role of antimicrobial peptides at the ocular surface.

McDermott. Alison M AM

The eye’s surface makes a natural antimicrobial peptide called LL‑37, which helps kill bacteria, fungi and viruses and may also speed up wound healing. While labs show it works well on its own and together with other peptides, there’s no ready‑to‑use supplement or dosage for everyday people yet.

Utility 2
pubmed May 19, 2008

Cathelicidin LL-37 in severe Streptococcus pyogenes soft tissue infections in humans.

Johansson. Linda L; Thulin. Pontus P; Sendi. Parham P; Hertzén. Erika E; Linder. Adam A; Akesso...

In severe strep skin infections, the body floods the wound with the antimicrobial peptide LL‑37, but the bacteria produce an enzyme (SpeB) that chops up LL‑37, making it ineffective at the infection site.

Utility 2
pubmed Feb 20, 2009

M1 protein allows Group A streptococcal survival in phagocyte extracellular traps through cathelicidin inhibition.

Lauth. Xavier X; von Köckritz-Blickwede. Maren M; McNamara. Case W CW; Myskowski. Sandra S; Zin...

The study shows that a protein (M1) made by a dangerous type of strep bacteria can block the human antimicrobial peptide LL‑37, letting the bacteria survive even inside the DNA traps that immune cells throw at them. This resistance is especially common in the most aggressive strains that cause severe infections.

Utility 2
pubmed Oct 20, 2008

Induction of group A Streptococcus virulence by a human antimicrobial peptide.

Gryllos. Ioannis I; Tran-Winkler. Hien J HJ; Cheng. Ming-Fang MF; Chung. Hachung H; Bolcome. Robert...

The study found that low, non‑killing amounts of the human immune peptide LL‑37 actually tell the strep bacteria to become more dangerous by making them produce more protective capsule and other harmful proteins, which helps them avoid being killed by immune cells.

Utility 2
pubmed Jul 22, 2009

Incorporation of antimicrobial compounds in mesoporous silica film monolith.

Izquierdo-Barba. Isabel I; Vallet-Regí. María M; Kupferschmidt. Natalia N; Terasaki. Osamu...

Scientists put the antimicrobial peptide LL-37 into tiny silica pores, letting it drip out slowly over about 200 hours. The material kills both Staph and E. coli well, and unlike a similar drug (chlorhexidine), it doesn’t damage cells. This suggests LL-37 could be used in implant coatings to prevent infections, but it isn’t a direct supplement or home‑use method.

Utility 2
pubmed Jun 2, 2008

The GraRS regulatory system controls Staphylococcus aureus susceptibility to antimicrobial host defenses.

Kraus. Dirk D; Herbert. Silvia S; Kristian. Sascha A SA; Khosravi. Arya A; Nizet. Victor V; Göt...

The study shows that the GraRS system in Staphylococcus aureus helps the bacteria resist the human antimicrobial peptide LL‑37 and immune cells by altering its surface charge. When GraRS is removed, the bacteria become more negatively charged, die more easily from LL‑37 and neutrophils, and cause less severe infections in mice.