Nori Porcine CCL17 ELISA Kit Summary

Alternative names for CCL17: Chemokine (C-C motif) ligand 17, TARC, SCYA17

Alternative names for porcine: Pig, swine

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: 

CCL17 is a powerful chemokine produced in the thymus and by antigen-presenting cells like dendritic cells, macrophages, and monocytes and is encoded by CCL17 gene.^[1] CCL17 plays a complex role in cancer. It attracts T-regulatory cells allowing for some cancers to evade an immune response. However, in other cancers, such as melanoma, an increase in CCL17 is linked to an improved outcome. CCL17 has also been linked to allergic diseases. CCL17 as well as its partner chemokine CCL22 induce chemotaxis in T-helper cells.^[1][2] They do this by binding to CCR4, a chemokine receptor.^[2] CCL17 is one of the few chemokines that are not stored in the body, except in the thymus; these chemokines are made when needed by dendritic cells, macrophages, and monocytes. CCL17 is expressed constitutively in the thymus, but only transiently in phytohemagglutinin-stimulated peripheral blood mononuclear cells. CCL17 can also be detected in other tissues such as the colon, small intestine, and lung. Granulocyte-macrophage colony-stimulating factor (GM-CSF) upregulates CCL17 production in monocytes and macrophages. Dendritic cells produce large quantities of CCL17 when stimulated with IL-4 or TSLP. CCL17 was the first CC chemokine identified that interacted with T cells with high affinity. CCL17 was also found to interact with monocytes, but with less affinity. It does not interact with granulocytes. It acts as a powerful chemoattractant to T-helper cells and T-regulatory cells because both can express CCR4. CCL17 is very important in the human body’s response to cancers. While it sometimes allows cancer to invade more rapidly, it more often helps the human body fight cancer.  CCL17 also activates tumor-infiltrating lymphocytes tumors. For many cancers, the more CCL17 in the area, the better the prognosis is for cancer survival or recovery. Like many cytokines, CCL17 is inflammatory, so while it plays a largely helpful role in attacking cancers, it can induce inflammatory diseases, including allergic skin diseases. CCL17 sometimes appears to worsen allergic diseases. CCL17 is known to help lymphocytes target areas on the skin, and could play a role in treatment of dermatitis and of other allergic reactions such as asthma. However, CCL17 is thought to trigger several Th2-mediated diseases. Atopic dermatitis(eczema) has been linked to CCL17, especially in infants whose mother does not have the disease.^[3] Studies have shown that children with allergies and atopic dermatitis have higher quantiles of CCL17 compared to children without allergies.^[3]

References

1. Imai T, et al. (1996) J Biol Chem 271 (35), 21514-21521.
2. Imai T, et al. (1997). The Journal of Biological Chemistry. 272 (23): 15036–42.
3. Furue M (2018). Journal of Cutaneous Immunology and Allergy. 1 (3): 93–99.