LL-37 (Human Cathelicidin)
LL-37 is the 37-residue C-terminal peptide of hCAP18, the only human cathelicidin, studied as a broad-spectrum antimicrobial effector of innate immunity that also signals to endothelial and epithelial cells in angiogenesis and wound-repair models, and the research catalog lists it at https://onesourcepeptides.com/product/ll-37.
The sequence came first. Gudmundsson et al., European Journal of Biochemistry, 1996 (PMID 8681941) characterized FALL39, the single human cathelicidin gene, mapped the mature antibacterial domain to exon 4, isolated the processed peptide from degranulated granulocytes, and identified it as LL-37, a potent antibacterial peptide in their assays. The same work flagged acute-phase response elements in the promoter, tying the gene to inflammatory signaling.
Knockout mice then showed the peptide family matters in living tissue. Nizet et al., Nature, 2001 (PMID 11719807) compared LL-37 with its mouse homologue CRAMP, found matching alpha-helical structures, antimicrobial spectra and tissue distribution, and showed that cathelicidins protect mouse skin against necrotic Group A Streptococcus infection, establishing them as a native component of innate host defense.
LL-37 also signals beyond microbes. Koczulla et al., Journal of Clinical Investigation, 2003 (PMID 12782669) reported that LL-37 drives angiogenesis through formyl peptide receptor-like 1 on endothelial cells, increasing endothelial proliferation and vessel-like structure formation in culture and producing neovascularization in the chorioallantoic membrane assay and a rabbit hind-limb ischemia model, while CRAMP-deficient mice showed reduced wound vascularization. In organ-cultured skin, Heilborn et al., Journal of Investigative Dermatology, 2003 (PMID 12603850) found the precursor hCAP18 strongly expressed in healing epithelium, with antibodies against LL-37 inhibiting re-epithelialization in a concentration-dependent way.
Wound-closure readouts like these are explained in Cell-migration readouts, in plain lab language, and lot identity belongs on the certificate of analysis for the vial in hand (see Are research peptides third-party tested?). LL-37 on the catalog is laboratory research supply only. This note summarizes published cell, tissue and animal research and is not dosing, reconstitution, or human-use guidance.