<i>In vitro</i> inhibition of tumour cell growth and DNA synthesis by peritoneal and lung macrophages from mice injected with <i>corynebacterium parvum</i>

Abstract

Abstract Peritoneal and lung macrophages from CBA mice injected with Corynebacterium parvum were tested for in vitro inhibition of growth and DNA synthesis of syngeneic tumour cells. Peritoneal macrophages inhibited the growth of RI leukaemia cells, and the DNA synthesis of RI leukaemia and T3 fibrosarcoma cells. Maximum inhibition of DNA synthesis was at 5 days after C. parvum injection. Inhibition was most effective when contact between macrophages and target cells was allowed, since medium from macrophage cultures was only slightly inhibitory. Macrophages maintained alone in culture for 48 h lost their ability to inhibit RI cell DNA synthesis. Lung macrophages inhibited the DNA synthesis of RI cells most effectively 14 days after C. parvum injection .