Technical datasheet
Description
Cathelicidins are a family of antimicrobial proteins predominantly found in the peroxidase-negative granules of neutrophils. During bacterial infections, the life span of neutrophils is regulated by various pathogen- and host-derived substances. The cathelicidins are synthesized as preproproteins. Within the neutrophils, they are stored in granules as inactive proforms after removal of the signal peptide. The active biologic domains of the cathelicidins generally reside in the C-terminus. The C-terminal antimicrobial peptides are activated when cleaved from the proforms of the cathelicidins by serine proteases from azurophil granules. Human cationic antimicrobial protein (hCAP)18 is the only human cathelicidin identified to date. hCAP18 (18 kD) is a major protein in specific granules of neutrophils, but it is also present in subpopulations of lymphocytes and monocytes, in squamous epithelia (of the mouth, tongue, esophagus, cervix, and vagina), pulmonary epithelium, keratinocytes in inflammatory skin diseases and in the epididymus. The antibacterial C-terminus of hCAP-18, LL37 (37 aminoacids), has been shown to exert broad antimicrobial activity towards gram-negative as well as gram-positive bacteria and to have synergistic antibacterial effects with the defensins. For instance deficiency in saliva LL37 accords with occurrence of periodontal disease in patients with morbus Kostmann. LL-37 does not only kill bacteria, but can also modulate (suppress) neutrophil apoptosis via the activation of FPRL1 and P2X7 in bacterial infections. Suppression of neutrophil apoptosis results in the prolongation of their life span, and may be advantageous for host defense against bacterial invasion. Moreover it functions as a chemotactic agent for neutrophils, monocytes and T cells. LL-37 is markedly resistant to proteolytic degradation and to a limited extent also cytotoxic towards mammalian cells.
Formulation
50 µg lyophilized, purified LL-37 peptide. Reconstitute the vial by injection with distilled or de-ionized water, volume depending on the concentration to be used.
Application
LL-37 can be used in biological assays.
Use
For testing of biological activity of LL-37 in vitro dilutions have to be made according to published references. It is recommended that users test the reagent and determine their own optimal concentrations.
Storage and stability
Lyophilized product should be stored at 4°C. Store stock solution in aliquots at -70°C. Repeated freeze and thaw cycles will cause loss of activity. Under recommended storage conditions, product is stable for one year.
References
- Johansson J, et al; Conformation-dependent antibacterial activity of the naturally occuring human peptide LL-37. J Biol Chem 1998, 273: 3718
- Agerberth B, et al; The human antimicrobial and chemotactic peptides LL-37 and alpha-defensins are expressed by specific lymphocyte and monocyte populations. Blood 2000, 96: 3086
- Yang D, et al; The role of mammalian antimicrobial peptides and proteins in awakening of innate host defences and adaptive immunity. Cell Moll Life Sci 2001, 58: 978
- Sørensen O, et al; Human cathelicidin, hCAP-18, is processed to the antimicrobial peptide LL-37 by extracellular cleavage with proteinase 3. Blood 2001, 97: 3951
- Saiman L, et al; Cathelicidin peptides inhibit multiply antibiotic-resistant pathogens from patients with cystic fibrosis. Antimicrob Agents Chemother 2001, 45: 2838
Precautions
For research use only. Not for use in or on humans or animals or for diagnostics. It is the responsibility of the user to comply with all local/state and Federal rules in the use of this product. Hycult Biotech is not responsible for any patent infringements that might result with the use of or derivation of this product.
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