Anti-CYFRA21-1 Antibody [D5]

The Antibodies.com Anti-CYFRA21-1 Antibody [D5] is a mouse monoclonal IgG1 reagent raised against the cytokeratin 19 (CK19) fragment known as CYFRA21-1, a soluble epithelial cytoskeletal marker shed into circulation by carcinoma cells. The D5 clone is a reference reagent in lung cancer research for measuring the CYFRA21-1 tumor marker, which is most strongly associated with non-small cell lung carcinoma (NSCLC) of squamous histology, and is also investigated in urothelial, cervical, and head-and-neck cancer cohorts.

Supplied as 1 mg of unconjugated antibody in a vial, the reagent is validated for western blot (WB), ELISA, chemiluminescence immunoassay (CLIA), and immunometric (ITM) assay workflows. For storage, aliquot immediately upon arrival and store frozen at -20 °C, avoiding repeated freeze-thaw cycles that can erode antigen-binding activity; for short-term bench use keep the vial refrigerated at 4 °C and protect it from prolonged light exposure.

Recommended starting conditions vary with application: typical working concentrations sit between 1 and 5 µg/mL for ELISA coating and around 1 to 2 µg/mL for western blot detection of CK19 in cell lysates and tissue extracts. Researchers commonly pair the D5 clone with complementary anti-CK19 antibodies such as BM19.21 or KS19.1 to build two-site immunometric assays, and the clone has been used in studies exploring CK19 fragments as circulating biomarkers in patient samples.