Susceptibility of normal and transformed cell lines to cytostatic and cytocidal effects exerted by macrophages.

Activated, nonimmune macrophages exerted profound effects on the proliferation and viability of eukaryotic target cells in vitro. Pronounced macrophage-mediated cytostasis was exerted on every rapidly proliferating cell line examined, irrespective of transformation, species derivation, cell type, or growth characteristics. However, the magnitude of cytostasis effected differed markedly among the 40 cell lines tested. There was no evident correlation between susceptibility to cytostasis and degree of transformation. Transformed cell lines with high and with low malignant attributes were affected equally. A comparable pattern was discerned for cytocidal effects of macrophages, in which the susceptibility of transformed targets was independent of the degree of malignancy.