A simple method of cell-mediated cytotoxic assay by postlabeling of tritiated thymidine

The cytotoxic reaction of effector cells on target cells was performed on cover slips which were set in a petri dish so as to be interposed from the dish surface through the bases of the slide glasses. After incubation, the target cells remaining on the cover slips were pulse-labeled with 3H-TdR for 45 min. Subsequently, the cover slips were removed from the bases, and dipped in cold 5% TCA to be freed from non-incorporated isotopes. The residual target cells adhering on the cover slips were counted without being removed. By this assay system, the specific or non-specific cytotoxicity of lymphocytes or macrophages was easily demonstrated with reliability.