Cathelicidins are a family of antimicrobial proteins predominantly found in the peroxidase-negative granules of neutrophils. 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. The antibacterial C-terminus of hCAP-18, LL37 (37 amino acids), 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. 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. LL-37 was demonstrated to be present in plasma in levels from 25 - 250 ng/ml and to be enhanced in infectious diseases.

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Datasheet URL	https://www.hycultbiotech.com/wp-content/uploads/2022/06/HK321-0816.pdf
Quantity	2 x 96 det.
Quantity	2 x 96 det.
Standard range	0.14-100 ng/ml
Detection level	0.14 ng/ml
Working volume	100 µl/well
Species	human
Application	The human LL-37 ELISA kit is to be used for the in vitro quantitative determination of human LL-37 in plasma and cell culture supernatant samples.
Principle	The human LL-37 ELISA is a ready-to-use solid-phase enzyme-linked immunosorbent assay based on the sandwich principle with a working time of 3½ hours. The efficient format of a plate with twelve disposable 8-well strips allows free choice of batch size for the assay. Samples and standards are captured by a solid bound specific antibody. Biotinylated tracer antibody will bind to captured human LL-37. Streptavidin-peroxidase conjugate will bind to the biotinylated tracer antibody. Streptavidin-peroxidase conjugate will react with the substrate, tetramethylbenzidine (TMB). The enzyme reaction is stopped by the addition of oxalic acid. The absorbance at 450 nm is measured with a spectrophotometer. A standard curve is obtained by plotting the absorbance (linear) versus the corresponding concentrations of the human LL-37 standards (log). The human LL-37 concentration of samples, which are run concurrently with the standards, can be determined from the standard curve.
Storage and stability	Product should be stored at 4 °C. Under recommended storage conditions, product is stable for at least six months.
Precautions	For research use only. Not for use in or on humans, 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.
References	1. Martineau, A et al; IFN-γ- and TNF-independent vitamin D-inducible human suppression of mycobacteria: the role of cathelicidin LL-37, J Immunol 2007, 178: 7190 2. Coffelt, S et al, Ovarian cancers overexpress the antimicrobial protein hCAP-18 and its derivative LL-37 increases ovarian cancer cell proliferation and invasion, Int J Cancer, 2008, 122: 1030 3. Bergsson, G et al; LL-37 Complexation with Glycosaminoglycans in Cystic Fibrosis Lungs Inhibits Antimicrobial Activity, Which Can Be Restored by Hypertonic Saline, J Immunol 2009, 183: 543 4. Cruse, G et al; Human Lung Mast Cells Mediate Pneumococcal Cell Death in Response to Activation by Pneumolysin, J Immunol 2010, 184: 7108 5. Schwaab, M et al; Human antimicrobial proteins in ear wax, Eur J Clin Microbiol Infect Dis 2011 6. Goleva, E et al; Steroid requirements and immune associations with vitamin D are stronger in children than adults with asthma, J Allergy Clin Immunol 2012 7. Lehouck, A et al, High Doses of Vitamin D to Reduce Exacerbations in Chronic Obstructive Pulmonary Disease, Ann Intern Med 2012, 156: 105 8. Levinson, P et al; HIV-Neutralizing Activity of Cationic Polypeptides in Cervicovaginal Secretions of Women in HIVSerodiscordant Relationships, Plos One 2012, 7:e31996
Disease	Autoimmunity, Infectious diseases

Applications
Application assays:	The human LL-37 ELISA kit is to be used for the in vitro quantitative determination of human LL-37 in plasma and cell culture supernatant samples.
Principle:	The human LL-37 ELISA is a ready-to-use solid-phase enzyme-linked immunosorbent assay based on the sandwich principle with a working time of 3½ hours. The efficient format of a plate with twelve disposable 8-well strips allows free choice of batch size for the assay. Samples and standards are captured by a solid bound specific antibody. Biotinylated tracer antibody will bind to captured human LL-37. Streptavidin-peroxidase conjugate will bind to the biotinylated tracer antibody. Streptavidin-peroxidase conjugate will react with the substrate, tetramethylbenzidine (TMB). The enzyme reaction is stopped by the addition of oxalic acid. The absorbance at 450 nm is measured with a spectrophotometer. A standard curve is obtained by plotting the absorbance (linear) versus the corresponding concentrations of the human LL-37 standards (log). The human LL-37 concentration of samples, which are run concurrently with the standards, can be determined from the standard curve.
Perfomance:	The linearity of the assay was determined by serially diluting a sample containing 35 ng/ml human LL-37. The diluted samples were measured in the assay. The line obtained a slope of 1.185 and a correlation coefficient of 0.999.

LL-37, Human, ELISA kit – 2 x 96 det. - HK321-02

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