Anti-Human Cytokeratin 18 (Clone LDK18) – Purified (PhenoCycler-Fusion (CODEX)® Ready)

Clone LDK18 has been validated for use on PhenoCycler® using [Mouse/Human] [Tissue] [Tissue Type either FFPE or FF] tissue.

Synthetic peptide of human keratin 18.

This purified antibody is formulated in 0.01 M phosphate buffered saline (150 mM NaCl) PBS pH 7.4.

This antibody is stable for at least one week when stored at 2-8°C. For long term storage, aliquot in working volumes without diluting and store at -20°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles.

LDK18 activity is directed against human Cytokeratin-18.

Cytokeratin-18 (CK18) is a structural marker protein specific to epithelial cells. CK18 is highly abundant in hepatocytes and cholangiocytes (epithelial cells of the bile duct). Additionally, CK18 is the main scaffold protein of keratinocytes produced by the intermediate filamentous filaments of most epithelial tissues (liver, lung, kidney, pancreas, gastrointestinal tract, mammary gland) as well as cancers that arise from these tissues. CK18 localizes to the cytoplasm and perinuclear region of the cell.

Cytokeratin-18 (CK18 or KRT18) is a cytoskeletal, type I intermediate filament protein¹ . CK18 is co-expressed with cytokeratin-8 (CK8), a type II intermediate filament protein ² , and together they form a flexible heterodimeric intracellular scaffold to structure the cytoplasm. CK18 is important for apoptosis, mitosis, cell cycle progression, and cell signaling and is particularly abundant in the liver, where it comprises 5% of total liver protein ^{2, 3} . CK18 is vital to liver development; knockout mice lacking CK18 develop liver lesions and tumors ² .

CK18 has clinical relevance to drug-induced liver disease and various cancers. During acute and chronic hepatocellular injury, necrotic cells passively release CK18 ² . The CK18 levels increase in serum and plasma ³ , and the degree of increase reflects the degree of necrotic hepatocellular injury and/or apoptosis ² . Full length CK18 contains two caspase consensus sites, DALD and VEVD, that are targeted during apoptosis to facilitate cytoskeleton degradation. Both full length CK18 and the caspase cleaved fragments (ccCK18) are prognostic markers for drug-induced liver injury ^{2, 3} . In clinical settings, CK18 and ccCK18 fragments can be readily quantified by immunoassays, with full length CK18 particularly useful in diagnosing early-stage drug-induced liver injury ² . Additionally, when pro- and anti-inflammatory cytokines are measured in combination with CK18 and ccCK18, the mechanism of hepatocellular injury (necrosis or apoptosis) can be determined.

CK18 also serves as a differential diagnostic marker in various cancers ¹ . Additionally, changes in CK18 expression are associated with poor prognosis in a variety of cancers, including esophageal squamous cell carcinoma, renal cell carcinoma, lung cancer, and some adenocarcinomas.

keratin 5, keratin 8, caspase 3, 14-3-3, TNF receptor II, plakophilin 2, EGF receptor, usherin

1. Weng YR, Cui Y, Fang JY. Mol Cancer Res. 10(4):485-493. 2012.
2. Korver S, Bowen J, Pearson K, et al. Arch Toxicol. 95(11):3435-3448. 2021
3. McGill MR, Jaeschke H. Adv Pharmacol. 85:221-239. 2019.
4. Fulzele A, Malgundkar SA, Govekar RB, et al. J Proteomics. 75(8):2404-2416. 2012.
5. McElroy SP, Nomura T, Torrie LS, et al. PLoS Biol. 11(6):e1001593. 2013.
6. Zupancic T, Stojan J, Lane EB, et al. PLoS One. 9(6):e99398. 2014.
7. Cao S, Yu S, Chen Y, et al. J Biol Chem. 292(46):19122-19132. 2017.
8. Lee MJ, Kim JY, Lee SI, et al. Cell Tissue Res. 325(2):253-261. 2006.