Cytotoxic T lymphocytes, and other death-inducing agents, have at least two different ways of killing their targets: drilling holes in the target cell membrane, or triggering the targets to commit suicide. The JAM Test is a method that measures the DNA fragmentation that accompanies cell suicide. We label target cells with radioactive DNA-precursor nucleotides and harvest them onto fiberglass filters, which trap large pieces of DNA but pass smaller fragments of apoptotic cells. As a general measure of apoptosis, the JAM Test described here is faster (can be completed in 4 h [or less if labeling is done the night before]), more quantitative, easier, more sensitive, more flexible and cheaper than most other current assays of apoptosis. The P-JAM, also discussed, additionally allows for assessment of death in cells that don't fragment their DNA, and allows for assays of agents that induce cell stasis rather than death.
Animals Cell Death