Anti-Keratin 18 (Ab-33) Antibody

This rabbit polyclonal reagent from Antibodies.com targets Keratin 18 (KRT18), a 45 kDa type I intermediate filament protein that forms obligate heterodimers with Keratin 8 in simple and glandular epithelia. The Ab-33 epitope is positioned within the head domain of KRT18, a region that is dynamically regulated by phosphorylation during mitotic entry, viral infection, and cellular stress responses, including p38 MAPK- and JNK-driven signaling. The unconjugated antibody is supplied as 100 µl in a vial and is validated for Western blot and immunohistochemistry on human samples. Common research uses include epithelial lineage tracing, carcinoma subtyping, hepatocyte and breast tissue studies, and identification of circulating tumor cells, where KRT18 is a robust epithelial marker widely paired with KRT8. It is also applied to investigations of caspase-mediated cleavage during apoptosis, because KRT18 is a caspase substrate and its cleavage fragments (such as those detected by the M30 antibody) are used as circulating biomarkers of epithelial cell death. Aliquot on receipt, store at -20 °C in a frost-free freezer, and avoid repeated freeze-thaw cycles to preserve reagent activity.