Disease and non-disease-related cell-mediated cytotoxicity in humans

The human bladder cancer/T24 system was used to investigate disease and non-disease-related cell-mediated cytotoxicity (CMC). CMC was determined in a modification of the microcytotoxicity assay of Takasugi and Klein. Analysis of data of groups of patients confirmed previous findings that effector cells (EC) from bladder cancer patients were more cytotoxic against T24 than were EC from normal individuals or from patients with other genitourinary cancers. Differences between patients with bladder cancer and other patients were not observed for other target cells. During the course of these experiments, non-disease-associated CMC by EC from individual normal donors and patients was observed. This phenomenon was investigated to determine its reproducibility and its relationship to different methods of preparing EC. Reproducibility of non-disease-related CMC was ascertained using EC prepared from heparinized blood by centrifugation over Ficoll-Hypaque (FH). A total of 126 experiments were performed in which 18 normal donors were tested 2 to 7 times each against 4 target cell lines. Of the resulting 46 combinations or groups of repeated assays, only 7 showed significant variability. Each normal donor had consistent CMC with differences from others being reproducible. CMC was therefore not due to crowding or physical effects. CMC mediated by EC prepared in this manner was then compared to that mediated by EC prepared by other methods in simultaneous tests.