Effects of antimitotic agents either free or bound to DNA on mouse peritoneal macrophages cultivated in vitro

Mouse peritoneal macrophages were cultivated in vitro and treated with ethidium bromide (EB) or with cis-dichloro-diammine platinum (II) (cis-Pt). EB provokes strong cytological alterations and cell degeneration; cis-Pt was not toxic under our experimental contitions. EB-DNA complex penetrates into the macrophages, is liberated from DNA in vacuoles, then diffuses into the cell and is highly cytotoxic. Cis-Pt-DNA complex also penetrates into the cells, but cis-Pt cannot be released from DNA, cis-Pt-DNA complex accumulates inside cytoplasmic vacuoles but has no cytotoxic activity.