What is LL-37?

LL-37, also called CAP-18 (catatonic antimicrobial protein 18), is an antimicrobial peptide expressed in almost all tissues and organs. It is produced by many cell types, including macrophages, airway epithelial cells, skin, and ocular epithelial cells, and natural killer (NK) cells. [R]

Multiple studies have been conducted on LL-37 since its discovery in 1995. These studies show that LL-37 induces an anti-cancer effect in colon cancer and gastric cancer. This natural peptide can also modulate the development of inflammatory and autoimmune diseases. [R][R][R]

In a mice model of collagen-induced arthritis, LL-47 reportedly played a protective role. It has also been found to kill gram-negative bacteria through direct anti-bacterial activities as well as modulation. Plus, it has been shown to promote wound closure in lung disease. [R][R][R]

LL-37 has also been shown to down-regulate the signaling of specific toll-like receptors (TLRs), thereby decreasing the production of pro-inflammatory cytokines. It has also exhibited anti-inflammatory effects, mainly by blocking the signaling of gram-negative bacteria. [R]

How Does LL-37 Work?

These are the proven functions of LL-37:

Modulates type 1 IFN responses

Type 1 interferons (INFs) are polypeptides secreted by infected cells. They have been shown to program and influence the development of innate and adaptive immunity. Type 1 IFNs also regulate antigen presentation, modulate natural killer (NK) cells’ function, and restrain viral pathogens. [R][R]

Regulates TLR function

Toll-like receptors (TLRs) are vital mediators of inflammatory pathways in the gut. LL-37 has been shown to down-regulate signaling through TLR4 via the binding of its ligand, LPS. This results in lower levels of pro-inflammatory cytokines when LL-37 and LPTS are present simultaneously. [R][R]

Modulates inflammation

Both pro- and anti-inflammatory functions have been assigned to LL-37. The difference may be explained by the disease background and the microenvironment it’s exposed to. [R]

Regulates Cell Death

LL-37 may promote or inhibit cell death, depending on the cell type involved and the context in which the simulation occurs. For example, higher doses of this peptide induce necrotic cell death in neutrophils. However, in other cells, it demonstrated an anti-apoptotic effect. [R]

Exerts antimicrobial activity

LL-37 has been proven to exert antimicrobial activity against bacteria, viruses, fungi, and parasites. Low concentrations of this peptide can prevent biofilm formation, and higher concentrations can destroy pre-existing biofilms. Biofilm-associated infections can cause death. [R][R]

Induces angiogenesis

Angiogenesis, or the formation of new blood vessels, is required for normal growth and development. It is also crucial for the healing of wounds. [R][R]

LL-37 Research

Following is a summary of the existing research on LL-37. The information given in this section is for educational purposes only. It doesn’t constitute medical advice. PureRawz sells LL-37 peptides for laboratory, educational, and scientific research purposes only.

LL-37 and Cancer

Various studies indicate that LL-37 plays a significant role in human cancer.

This peptide has been found to play an anti-cancer effect in colon cancer, gastric cancer, hematologic malignancy (cancers that begin in blood-forming tissue such as bone marrow), and oral squamous cell carcinoma (a tumor that occurs within the oral cavity). [R]

However, not all of its cancer effects are tumor-killing. LL-37 has also been found to induce cancer development, such as for ovary, breast, prostate, pancreas, and lung cancers. More research is needed to explore the cancer-specific effects of this peptide further. [R]

LL-37 and Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune disease that affects joints in the hands, wrists, and knees.

According to research, LL-37 inhibits the development of this disease via down-regulating pro-inflammatory cytokines. Furthermore, low doses of this peptide have been shown to decrease joint inflammation in arthritic mice. [R] [R]

Another preclinical study reported that LL-37-derived peptide conferred protection in a mice model of collagen-induced arthritis. The peptide, which was an internal segment of LL-37, decreased disease severity and significantly reduced serum levels of antibodies against collagen type II. [R]

LL-37 and Psoriasis

Psoriasis is a disease that causes patches of thick red skin and silvery scales.

Preclinical studies showed LL-37 inducing keratinocyte apoptosis in a psoriasis model. Keratinocytes are the major cell type of the outermost layer of the skin, making about 90% of cells there. Psoriasis is characterized by keratinocyte proliferation, something which LL-37 prevents. [R][R]

However, while the above research demonstrates the anti-inflammatory activity of LL-37 in psoriasis skin, other studies highlight its pro-inflammatory effects. Thus, studies in patients under treatment could lead to a better understanding of the role of LL-37 in psoriasis. [R]

LL-37 and Bacteria

In preclinical research, LL-37 has demonstrated moderate antimicrobial activity against numerous gram-negative and gram-positive bacteria, which can cause skin infections. [R]

It has been reported that LL-37 could kill bacteria through direct anti-bacterial activities as well as through modulating the immune system (immunomodulation). The direct action includes disrupting the bacteria’s membrane, which disrupts cell integrity and, eventually, cell death. [R]

The immunomodulatory activities involve inducing cell migration, proliferation, and differentiation. Still, challenges remain before LL-37 can get regulatory approval as an anti-bacterial agent. These challenges include high costs, lower activity in physiological environments, and more. [R]

LL-37 and Intestine

Research in cell cultures has indicated several effects of LL-37, including increased migration of cells necessary for maintaining the intestine’s epithelial barrier and reduced cell death in intestinal inflammation. [R]

Its effects in the intestine make LL-37 a potential therapeutic candidate for acute intestinal infections, such as inflammatory bowel disease.

LL-37 and COPD

Chronic obstructive pulmonary disease, or COPD, refers to a group of diseases that cause airflow blockage and breathing-related problems. Around 16 million Americans have this lung disease. [R]

According to a clinical study in patients with COPD, the plasma levels of LL-37 were lower in COPD patients with a high risk of frequent exacerbations than in healthy subjects. Thus, low levels of this peptide might be predictors of exacerbation risk in COPD patients. [R]

LL-37 and Toxic Dust Syndrome

Organic toxic dust syndrome is common in agricultural workers. It is characterized by fever occurring 4 to 12 hours after exposure and flu-like symptoms. [R]

In vitro, research has shown that bacterial lipopolysaccharide (LPS) plays an important role in the pathogenesis of ODTS. This is important because LL-37 has been shown to neutralize this LPS and thus holds potential as a therapeutic agent for serious bacterial infections. [R]

Frequently Asked Questions

Is LL-37 a Cathelicidin?

LL-37 is the only human member of the cathelicidin family. Cathelicidins are antimicrobial peptides (AMPs) found in humans and other species, such as farm animals. They are part of your immune system and protect the body from microbial attacks of viruses, bacteria, and fungi. [R]

What does LL-37 do in the lungs?

Natural LL-37 has demonstrated various cellular activities in the lungs, such as killing a broad spectrum of microorganisms, cytotoxicity to epithelial cell proliferation, and angiogenesis. More research is needed to understand how normal lung tissue responds to LL-37. [R]

Where to Buy LL-37 Online?

PureRawz is the best place to buy the highest-quality LL-37 online.

In order to be the best supplier of research chemicals, we provide reference materials with every product we sell. All of our products come with an independent, third-party-issued Certificate of Analysis for identification, purity, and concentration.

We offer free international shipping on all orders above $100. You can pay for your purchase through various methods, including PayPal and Bitcoin.

Summary

LL-37 peptide possesses anti-inflammatory, anti-fungal, and antimicrobial properties.

Preclinical studies have shown that it can encourage blood vessels’ growth, inhibit inflammatory arthritis, and promote wound closure/wound healing. It can also modulate the pathogenesis of autoimmune and inflammatory diseases and inhibit gastric cancer cell proliferation.

PureRawz sells LL-37 for laboratory and research use only.