Description

Nori Equine Calprotectin ELISA Kit Summary

Alternative names for calprotectin: dimer of calcium binding proteins S100A8 and S100A9

Alternative names for equine: Horse

Standard Curve

Kit Components
1. Pre-coated 96-well Microplate
2. Biotinylated Detection Antibody
3. Streptavidin-HRP Conjugate
4. Lyophilized Standards
5. TMB One-Step Substrate
6. Stop Solution
7. 20 x PBS
8. Assay Buffer

Other Materials Required but not Provided:
1. Microplate Reader capable of measuring absorption at 450 nm
2. Log-log graph paper or computer and software for ELISA data analysis
3. Precision pipettes (1-1000 µl)
4. Multi-channel pipettes (300 µl)
5. Distilled or deionized water

Protocol Outline
1. Prepare all reagents, samples and standards as instructed in the datasheet.
2. Add 100 µl of Standard or samples to each well and incubate 1 h at RT.
3. Add 100 µl of Working Detection Antibody to each well and incubate 1 h at RT.
4. Add 100 µl of Working Streptavidin-HRP to each well and incubate 20 min at RT.
5. Add 100 µl of Substrate to each well and incubate 5-30 min at RT.
6. Add 50 µl of Stop Solution to each well and read at 450 nm immediately.

Background: 

Calprotectin is a 24 kDa dimer of calcium binding proteins S100A8 and S100A9.^[1] The complex accounts for up to 60% of the soluble protein content of the neutrophil cytosol. In vitro studies show that calprotectin has bacteriostatic and fungistatic properties, that arise from its ability to sequester manganese and zinc.^[1] Calprotectin has two transition metal binding sites that form at the interface of the S100A8 and S100A9 monomers, and metal sequestration by calprotectin has been shown to be calcium dependent.^[1] The complex is resistant to enzymatic degradation, and can be easily measured in faeces.^[2] Fecal calprotectin is a biochemical measurement of the protein calprotectin in the stool. Elevated faecal calprotectin indicates the migration of neutrophils to the intestinal mucosa, which occurs during intestinal inflammation, including inflammation caused by inflammatory bowel disease. Under a specific clinical scenario, the test may eliminate the need for invasive colonoscopy or radio-labelled white cell scanning. The main diseases that cause an increased excretion of faecal calprotectin are inflammatory bowel diseases, coeliac disease, infectious colitis, necrotizing enterocolitis, intestinal cystic fibrosis and colorectal cancer.^[3] Although a relatively new test, faecal calprotectin is regularly used as indicator for inflammatory bowel diseases (IBD) during treatment and as diagnostic marker. IBD are a group of conditions that cause a pathological inflammation of the bowel wall. Crohn’s disease and ulcerative colitis are the principal types of inflammatory bowel disease. Inflammatory processes result in an influx of neutrophils into the bowel lumen.^[4] Since calprotectin comprises as much as 60% of the soluble protein content of the cytosol of neutrophils, it can serve as a marker for the level of intestinal inflammation.^[5] Measurement of faecal calprotectin is considered the gold standard measurement of intestinal inflammation.^[6] Levels of faecal calprotectin are usually normal in patients with irritable bowel syndrome (IBS).^[7] In untreated coeliac disease, concentrations of faecal calprotectin correlate with the degree of intestinal mucosal lesion and normalize with a gluten-free diet. Although faecal calprotectin correlates significantly with disease activity with confirmed IBD, faecal calprotectin can be false-positive if the laboratory uses low calprotectin cut-off levels.^[7] Most importantly, intake of non-steroidal anti-inflammatory drugs (aspirin included) increases calprotectin values, possibly due to the associated induced enteropathy.

References

1. Brophy MB, Nolan EM (2015). ACS Chemical Biology. 10(3): 641–51.
2. Tibble J, et al. (2000). Gut. 47(4): 506–13.
3. Konikoff MR, et al. (2006). Inflammatory Bowel Diseases (Review). 12(6): 524–34.
4. Walsham NE, et al. (2016). Clinical and Experimental Gastroenterology. 9: 21–9.
5. Stríz I, Trebichavský I (2004). Physiological Research. 53(3): 245–53.
6. Costa F, et al. (2003). Digestive and Liver Disease. 35(9): 642–7.
7. Waugh N, et al. (2013) Health Technology Assessment (Review) 17(55): xv–xix, 1–211.

Product Citation