Cytokeratins are intermediate filament proteins that are widely expressed in many tissues. These proteins are vital components of the cytoskeleton and interact with a number of other proteins. Cytokeratins are usually found in the cytoplasm,although some cytokeratins can be found in the nucleus and the nucleolus. The C-11 monoclonal antibody reacts with conserved epitope in all species tested of cytokeratin 4, 5, 6, 8, 10, 13, and 18. This antibody has been shown to be useful for Western blotting and has also been reported to be useful for immunoprecipitation, immunohistochemistry (paraffin sections), and immunocytochemistry.