Cytokeratin-18 expression has been shown in but is not limited to cells and tissues from lung, breast, intestine, gut, colon, kidney, pancreas, bladder, trophoblasts.
The M30‑Apoptosense^® ELISA uses the well-established M30 CytoDEATH monoclonal antibody which has been shown in numerous independent studies to be specific to the CK18 Asp³⁹⁶ caspase cleavage site and represents a validated apoptosis marker that does not react with viable or necrotic cells.

Apoptosis detection using M30 CytoDEATH has been described in several publications to serve as a superior technique compared to TUNEL or detection of gammaH2AX phosphorylation. Assessment of apoptosis by immunohistochemical markers compared to cellular morphology in ex vivo‑stressed colonic mucosa under conditions of DNA-damage may be repaired and results in false-positive counts of apoptotic cells. In addition has modest or transient caspase activation without the cleavage of death substrates been attributed to non-suicidal processes such as proliferation, differentiation and inflammation.

The unmatched sensitivity and superior performance characteristics of M30‑Apoptosense® ELISA even allows the tracing of apoptotic epithelial cells (e.g. carcinoma cells) in human blood samples as no contribution comes from apoptotic inflammatory lymphoid cells as those belong -together with neuronal cells and tissues- to the prominent populations of Cytokeratin-18 negative cells.

By measuring the caspase-cleaved Cytokeratin-18 with M30 one can selectively quantify the extent of non-lympoid e.g. epithelial carcinoma target cells in natural killer (NK) activity tests in one well containing a mixed cell population of otherwise un-labeled effector (T cells: CK18 and M30 negative) and target cells (carcinoma cells: CK18 and M30 positive).

As the principle of the M30‑Apoptosense^® ELISA is based upon measuring the rapid accumulation of a caspase cleavage product -that is comparably stable- rather than proteolytic activity itself, it is recommended as an advantageous assay for high through‑put screening (HTS) selective for pro-apoptotic compounds:
- It avoids the necessity to analyse multiple time‑points after the apoptotic stimulus as it has the broadest time-window for optimal signal strength compared to alternative apoptosis detection methods as it does not rely on cell proliferation M30‑Apoptosense^® ELISA avoids false positive counts due to cell cycle arrest, senescence or differentiation.
- For mechanistically studies the optional analysis of only the cell culture supernatant avoiding cell lysis allows the ongoing manipulation of the cells to study sensitization or synergistic effects of different stimuli (e.g. drugs) in the same tissue culture well.

Please also see our Product Flyer "M30 CytoDEATH™ - Key Marker to Detect Apoptosis in Epithelial Cells" and the Original Manufacturer’s Product Description.