Measurement of tumor cytolysis by macrophages.

This unit describes two different protocols for the measurement of tumor cytolysis by macrophages. Traditionally, cytotoxicity assays have relied on the use of radioactive isotopes. In Basic Protocol 1, cytotoxic activity is measured by the release into the culture supernatant of a radioisotope that had been incorporated by the target cell and is released upon cell death. This poses a problem for some cell lines in which spontaneous isotope release occurs in the absence of effector cell cytotoxicity. In Basic Protocol 2, a nonradioactive approach is used to measure cytolysis that relies on the fluorescence staining of tumor cells with cell-death markers. It also provides the obvious advantage of avoiding the use of hazardous radioactive materials.