An antimicrobial peptide of the cathelicidin family that provides innate immune defense by killing pathogens and modulating inflammation and wound healing.
Scheenstra. Maaike R MR; van den Belt. Matthias M; Tjeerdsma-van Bokhoven. Johanna L M JLM; Schneide...
The study compares three antimicrobial peptides—human LL‑37, pig PMAP‑36, and chicken CATH‑2—and finds they kill bacteria in different ways and affect the immune system differently. LL‑37 doesn’t stick to bacterial LPS very well but still blocks LPS‑driven inflammation strongly, while PMAP‑36 binds LPS well but is less effective at stopping inflammation. Shortening PMAP‑36 removes some activity, and the smaller versions need to pair up (dimerize) to keep their immune‑modulating effects.
Nocerino. Rita R; De Filippis. Francesca F; Cecere. Gaetano G; Marino. Antonio A; Micillo. Maria M;...
A study in breastfed babies with colic found that giving the probiotic Bifidobacterium animalis subsp. lactis BB‑12 for 28 days cut crying time by at least half in many infants. The probiotic also boosted beneficial gut bacteria, short‑chain fatty acids, and immune proteins like the antimicrobial peptide LL‑37, while lowering gut inflammation markers.
Majewski. Karol K; Kozłowska. Elżbieta E; Żelechowska. Paulina P; Brzezińska...
The study measured the natural immune peptide LL‑37 in the blood of people with different kinds of bacterial pneumonia and compared it to healthy people. It found higher levels when the infection was caused by common bacteria like strep or Haemophilus, but lower levels when the infection was from tougher, opportunistic bugs. This suggests LL‑37 is part of the body’s fight against lung infections, and low levels might mean a weaker immune response.
Agha. Nadia H NH; Baker. Forrest L FL; Kunz. Hawley E HE; Spielmann. Guillaume G; Mylabathula. Prete...
During a six‑month stay on the International Space Station, astronauts showed higher levels of the natural antimicrobial peptide LL‑37 (along with other immune proteins) in their saliva, especially before launch and early in the mission. First‑time flyers had the biggest spikes, and those who re‑activated latent viruses also had higher stress hormones.
Martynowycz. Michael W MW; Rice. Amy A; Andreev. Konstantin K; Nobre. Thatyane M TM; Kuzmenko. Ivan...
The study shows that Salmonella can change its outer membrane to become twice as resistant to the human antimicrobial peptide LL‑37, meaning the peptide needs higher doses to work against these modified bacteria. The changes make the membrane more ordered, which blocks the peptide from getting inside, though the initial sticking to the membrane is still the same.
Dahl. Sara S; Cerps. Samuel S; Rippe. Catarina C; Swärd. Karl K; Uller. Lena L; Svensson. Danie...
The study shows that the human peptide LL‑37 can enter vascular smooth muscle cells and makes them react more strongly to double‑stranded RNA (a viral‑like signal) by increasing inflammation‑related proteins. This happens because LL‑37 raises the amount of the dsRNA sensor TLR3, and the effect disappears when TLR3 is blocked.
Yilmaz. Dogukan D; Topcu. Ali Orkun AO; Akcay. Emine Ulku EU; Altındis. Mustafa M; Gursoy. Ulv...
People with type 2 diabetes have different levels of natural antimicrobial proteins in their saliva. Diabetes lowers the defensins (hBD‑1, hBD‑2, hBD‑3) but raises cathelicidin (LL‑37), especially when gum disease is also present. These changes are linked to blood sugar levels (HbA1c) and gum inflammation.
Dean. Scott N SN; Milton. Morgan E ME; Cavanagh. John J; van Hoek. Monique L ML
Scientists studied a protein called BfpR in a bacterium and found that when this protein is missing, the bacteria become more resistant to the human antimicrobial peptide LL‑37. The same change also makes the bacteria form more biofilm and grow better inside human immune cells.
The study shows that the natural antimicrobial peptide LL-37 is produced by human eye cells when infected with the bacteria that cause eye infections, and that LL-37 can kill those bacteria. Its production depends on a cell signaling protein called STAT3, and blocking STAT3 reduces LL-37 levels.
Macleod. Tom T; Ward. Joseph J; Alase. Adewonuola A AA; Bridgewood. Charlie C; Wittmann. Miriam M; S...
The study shows that the skin protein LL‑37 can grab onto a therapeutic RNA aptamer and pull it into skin cells without triggering inflammation or interferon signals. This means that in inflamed skin, like psoriasis or eczema, LL‑37 could help deliver RNA‑based drugs inside cells safely, but the research is still early and not a ready‑to‑use recipe.
Xu. Ning N; He. Daikun D; Shao. Yiru Y; Qu. Yubei Y; Ye. Kaili K; Memet. Obulkasim O; Zhang. Lin L;...
In rats exposed to a toxic gas, tiny particles called exosomes released from the lungs can boost stem cells' growth, movement, and anti‑inflammatory signals, including more of the peptide LL‑37. This effect is driven by a small RNA (miR‑28‑5p) that activates the PI3K/Akt pathway in the stem cells.
Peng. Lianci L; Du. Wenjuan W; Balhuizen. Melanie D MD; Haagsman. Henk P HP; de Haan. Cornelis A M C...
Scientists tested several cathelicidin peptides, including the human peptide LL‑37, against flu viruses in a dish. They found that a chicken peptide called CATH‑B1 could cut infection rates by up to 80%, but LL‑37 barely worked. The chicken peptide works by sticking to the virus and clumping it together, which blocks the virus from entering cells.
Dahl. Sara S; Anders. Emma E; Gidlöf. Olof O; Svensson. Daniel D; Nilsson. Bengt-Olof BO
The study shows that the antimicrobial peptide LL-37 can get inside human mast cells and, at relatively high levels (4‑10 µM), it hurts the cells and makes them spill their DNA, proteins and enzymes, but it doesn’t cause the cells to form the usual “net‑like” traps seen with other stimulants. Lower doses (1 µM) didn’t harm the cells in the lab test.
Horie. Toshi T; Inomata. Megumi M; Into. Takeshi T
The study shows that a gum‑disease bacterium, Porphyromonas gingivalis, uses special surface proteins (Pgm6/Pgm7) to hide from the human antimicrobial peptide LL‑37. When those proteins are removed, LL‑37 sticks to the bacteria and kills it more easily, and it even works better together with other natural peptides. This explains why simply boosting LL‑37 may not clear this bug on its own.
Gupta. Sudipti S; Preece. Janae J; Haynes. Andria A; Becknell. Brian B; Ching. Christina C
Researchers measured several antimicrobial peptides in the urine of kids with neurogenic bladders and found that one of them, NGAL, was higher in true infections than in harmless bacterial presence, making it a possible test to tell the two apart.
Postolache. Teodor T TT; Akram. Faisal F; Lee. Ellen E EE; Lowry. Christopher A CA; Stiller. John W...
Researchers looked at brain tissue from people who died by suicide and found that the vitamin D receptor was higher while the antimicrobial peptide LL‑37 was lower compared to matched controls. This pattern matches what we know about vitamin D deficiency being linked to immune changes and mood problems, but the study only shows a correlation, not a cause‑and‑effect or a treatment tip.
The study found that the natural peptide LL-37 is higher in nasal polyps and makes neutrophils release web‑like traps (NETs) that can worsen inflammation. This effect happens even when steroids are used, and people with the condition are more sensitive to LL-37.
The study measured levels of the antimicrobial peptide LL-37 and two beta‑defensins in people with active tuberculosis. In severe lung TB, beta‑defensin‑3 was high but dropped after treatment, while LL‑37 stayed normal at first and rose during therapy. In pleural TB, beta‑defensin‑2 was low but beta‑defensin‑3 and LL‑37 were higher, suggesting different immune roles in the two disease forms.
Shahid. Muhammad M; Cavalcante. Paloma Araujo PA; Knight. Cameron G CG; Barkema. Herman W HW; Han. B...
The study shows that the human peptide LL‑37 can directly kill the algae Prototheca bovis, which causes infections in cows and sometimes in humans, and it also calms down inflammation in mouse immune cells. In mice, their own cathelicidin (Camp) makes inflammation worse but doesn’t kill the algae.
Zughaier. Susu M SM; Rouquette-Loughlin. Corinne E CE; Shafer. William M WM
The study found that the gonorrhea bacteria carry a protein that works like human HDAC enzymes and can turn down the body’s natural antibiotic peptide LL‑37 (as well as other defense proteins) by changing the DNA packaging in immune cells. When the bacteria lack this HDAC‑like protein, LL‑37 levels stay higher.