Lymphatic Cytolytic Function
The innate complexity of the immune system includes a line of defense against virally infected and carcinogenic cells, a type of cytotoxic lymphocyte critical to the innate immune system called Natural Killer (NK) cells. Current methods to study the cytolytic function of NK cells are typically low-throughput, destructive, and do not adequately mimic in vivo conditions. Traditional cell-mediated cytotoxicity assays rely on the release of internal cellular components of lysed cells or from the uptake of a viability marker to detect dead cells. One of the most popular cytotoxicity assays is the Chromium Release Assay where target cells are radioactively labeled with protein-bound 51Cr and co-cultured with effector cells. Once cells are dead or dying, they will release the bound 51Cr and this is measured by gamma detection. This method is very difficult to standardize, hazardous, and has scalability and time-constraint limitations as it can only be performed in short intervals of 4 to 24-hour time points.
Accurate Alternative Cytotoxicity Assay
An alternative to Chromium release is the detection of non-radioactive labels like Lactate dehydrogenase (LDH) and Calcein AM with the help of a plate reader. This removes the radioactive hazard but it is still difficult to standardize as your measurement is based on whole-well levels of the released marker. A second alternative is to use flow cytometry coupled with a dead viability dye that would enter dead and dying cells and be fluorescently detected. All three of these assays offer a method for cytotoxicity detection but require handling of hazardous chemicals, tedious hours at a detection machine, or offer low-sensitivity readings, and neither provide a high-throughput non-destructive method of detection. This is where the Celigo Image Cytometer can offer a solution.