An antimicrobial peptide of the cathelicidin family that provides innate immune defense by killing pathogens and modulating inflammation and wound healing.
The study shows that the human antimicrobial peptide LL‑37 can bind bacterial toxin LPS and help liver cells pull it out of the bloodstream for destruction, doing so without turning on inflammatory signals. This was seen in lab‑grown liver cells, not in people, and no dosage or safety info was provided.
Zhang. Yuan-Yuan YY; Yu. Yang-Yang YY; Zhang. Ya-Rui YR; Zhang. Wei W; Yu. Bo B
LL-37, a natural antimicrobial peptide, can make human mast cells release chemicals that cause allergy‑type reactions. However, when the cells are also exposed to TLR2‑activating molecules (like peptidoglycan or Pam3CSK4), the allergic response is dampened, and the cells shift toward a more general immune‑defense mode. The study was done in a lab cell line, not in people, so the findings are early‑stage.
Piktel. Ewelina E; Niemirowicz. Katarzyna K; Wnorowska. Urszula U; Wątek. Marzena M; Wollny. T...
LL-37 is a natural peptide that can either help or hurt cancer growth depending on the organ. It’s higher in some cancers like ovarian, lung and breast, but lower in others like colon and stomach. The peptide works by binding to different cell‑surface receptors, so its effect changes with the type of tissue.
Coorens. Maarten M; Scheenstra. Maaike R MR; Veldhuizen. Edwin J A EJ; Haagsman. Henk P HP
The study compared 12 cathelicidin peptides from different animals and found that their antimicrobial strength, ability to neutralize bacterial toxins, and immune‑modulating effects vary a lot. Some work well against E. coli, others against MRSA, and only a few boost certain immune pathways. This means you can’t assume that the human peptide LL‑37 behaves the same as cathelicidins from other species.
Alt. Jeremiah A JA; Qin. Xuan X; Pulsipher. Abigail A; Orb. Quinn Q; Orlandi. Richard R RR; Zhang. J...
A mouse study found that putting the immune peptide LL‑37 into the nose causes strong, dose‑dependent inflammation in the smell‑sensing tissue, bringing in immune cells like neutrophils and mast cells. This suggests that using LL‑37 topically in the nasal area could irritate and damage the lining rather than help.
The study shows that the human antimicrobial peptide LL‑37 (and its pig counterpart PR‑39) rises when neutrophils move into the brain's fluid space during a Streptococcus suis infection, and that it helps keep the neutrophil traps (NETs) from being broken down by bacterial enzymes.
Larcombe. Linda L; Mookherjee. Neeloffer N; Slater. Joyce J; Slivinski. Caroline C; Dantouze. Joe J;...
In a small study of 34 Canadian First Nation adults, taking 1,000 IU of vitamin D each day didn’t raise blood vitamin D levels and actually lowered the immune peptide LL‑37, especially in people with certain genetic variants.
The study shows that a protein made by the sexually transmitted bacteria Chlamydia (called Pgp3) can stick to and block the human antimicrobial peptide LL‑37, which normally helps kill microbes in the genital tract and skin. This means the bacteria can protect itself from LL‑37, and the part of Pgp3 that does this could be a target for new treatments.
Barksdale. Stephanie M SM; Hrifko. Evelyn J EJ; van Hoek. Monique L ML
Scientists found a natural antimicrobial protein from alligator blood that can kill tough, drug‑resistant bacteria like Acinetobacter and Klebsiella. The peptide works by punching holes in bacterial membranes, isn’t killed by salt, and doesn’t harm human cells or red blood cells at the tested doses. It could become a new kind of anti‑infection drug, but it’s still early‑stage research.
Wright. Thomas K TK; Gibson. Peter G PG; Simpson. Jodie L JL; McDonald. Vanessa M VM; Wood. Lisa G L...
The study found that sticky DNA webs called NETs, which contain the antimicrobial peptide LL‑37, are higher in the sputum of people with asthma and COPD, especially when the disease is driven by neutrophils. More NETs were linked to worse lung function, more inflammation, and severe disease, but the research didn’t test any treatments to lower NETs.
Han. Jenny E JE; Jones. Jennifer L JL; Tangpricha. Vin V; Brown. Mona A MA; Brown. Lou Ann S LAS; Ha...
Giving very high doses of vitamin D3 (250,000–500,000 IU total over 5 days) to critically ill patients on ventilators safely raised their blood vitamin D levels and shortened their hospital stay, but it didn’t change the levels of the antimicrobial peptide LL‑37 or any other major health outcomes.
Boge. Lukas L; Bysell. Helena H; Ringstad. Lovisa L; Wennman. David D; Umerska. Anita A; Cassisa. Vi...
Scientists tested liquid‑crystal carriers (tiny gel‑like particles) to protect antimicrobial peptides, including LL‑37. While the carriers didn’t change the liquid‑crystal structure, loading LL‑37 into them actually reduced its ability to kill bacteria, unlike some other peptides. This suggests LL‑37 may be unstable or less effective when delivered in these specific lipid particles.
The study shows that the antimicrobial peptide LL-37 can talk to a gut immune receptor (FPR2) on special cells that help B‑cells work. This signaling makes the gut produce more signals (CXCL13 and BAFF) that tell B‑cells to grow and make IgA antibodies, which protect the intestine.
Dutta. Debarun D; Kumar. Naresh N; D P Willcox. Mark M
Scientists stuck a few antimicrobial peptides, including LL‑37, onto a plastic surface and saw that LL‑37 could cut down one type of bacteria (Pseudomonas) but not another (Staph). The coating didn’t hurt mouse cells, showing it’s safe for the material, but the effect was modest compared to other peptides.
Mishra. Biswajit B; Golla. Radha M RM; Lau. Kyle K; Lushnikova. Tamara T; Wang. Guangshun G
Researchers tested short versions of the human antimicrobial peptide LL‑37 and found that two of them, especially a 17‑amino‑acid peptide called 17BIPHE2, can stop MRSA bacteria from sticking together and can even break down existing bacterial films in lab dishes. The original full‑length LL‑37 only stopped new films from forming and didn’t affect already‑attached bacteria. These findings are still early‑stage and done in test‑tube models, not in people.
Rompikuntal. Pramod K PK; Vdovikova. Svitlana S; Duperthuy. Marylise M; Johnson. Tanya L TL; Åh...
The study shows that the cholera bacterium releases tiny packages called outer membrane vesicles that carry an active enzyme, PrtV, which can damage human cells and also protect the bacteria from the natural antimicrobial peptide LL‑37. This means that LL‑37’s ability to kill such bacteria can be reduced by this bacterial defense mechanism.
Malanovic. Nermina N; Leber. Regina R; Schmuck. Maria M; Kriechbaum. Manfred M; Cordfunke. Robert A...
OP-145, a lab‑made version of the natural peptide LL‑37, can kill Staph bacteria by messing with the bacterial membrane, but at higher amounts it also tears apart human cell membranes. The way it works is different for bacterial vs. human‑like membranes, but its shape stays the same. Calcium levels don’t change its activity.
Cha. Ha-Ram HR; Lee. Joo Hyoung JH; Hensel. Jonathan A JA; Sawant. Anandi B AB; Davis. Brittney H BH...
The study shows that the antimicrobial peptide LL‑37 (called CRAMP in mice) can actually help prostate tumors grow by pulling in immature immune cells and turning them into tumor‑friendly M2 macrophages. When the peptide is reduced in tumor cells, tumors grow slower, suggesting that high LL‑37 might be a risk factor for cancer progression, at least in this mouse model.
Braun. Katharina K; Pochert. Alexander A; Lindén. Mika M; Davoudi. Mina M; Schmidtchen. Artur A...
The study shows that the way LL‑37 is packaged matters a lot. Negatively charged, porous silica particles can hold a lot of the peptide, protect it from being broken down, and release it when it meets bacterial membranes. Non‑porous or positively charged silica particles either stick the peptide to their surface or cause unwanted damage to human cells.
Bierkarre. H H; Harder. J J; Cuthbert. R R; Emery. P P; Leuschner. I I; Mrowietz. U U; Hedderich. J...
The study found that the antimicrobial peptide LL‑37 and several other immune proteins are abundant in psoriasis skin but are not present in joint tissue of psoriatic arthritis or rheumatoid arthritis patients. This suggests the skin and joints use different immune defenses, which may explain why some people with psoriasis don’t develop joint disease.