In vitro suppression of macrophage spreading caused by supernatants of tumour, thymus, and lymph node cells.
Peritoneal macrophages washed out from C3Hf/Bu mice were cultivated in medium 199 supplemented with 35% foetal calf serum. If the pH of the medium was adjusted to 7.2, there were 70% spread macrophages after six hours of incubation at 37 degrees C. We investigated the effect of tumour cells on macrophage spreading. Supernatants from cell cultures of a fibro-sarcoma of C57BL mice and lymphoma of C3Hf/Bu mice were used to determine the number of spread macrophages after 6 hours of culture in these supernatants. Supernatants from cell cultures of the kidney, thymus and lymph nodes of normal C57BL or C3Hf/Bu mice and peritoneal cells of normal C3Hf/Bu mice in medium 199 alone served as control. We observed that supernatants from both allogeneic and syngeneic tumour cell cultures reduced significantly the percentage of spread macrophages in comparison with the percentage of spread macrophages found in the kidney culture supernatants. However, a similar spreading inhibition was caused also by supernatants from the thymus and lymph node cell cultures. In these experiments we confirmed the earlier observations that tumour cells can suppress the activation of macrophages, and we also pointed to the possibility that this effect is not specific only for malignant tissues.
D000818:Animals; D002478:Cells, Cultured; D005354:Fibrosarcoma; D008198:Lymph Nodes; D008223:Lymphoma; D008264:Macrophages / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D009374:Neoplasms, Experimental; D013950:Thymus Gland