Effect of carrageenan on the non-specific resistance of mice to injected syngeneic tumour cells, alone or in mixtures.
The mechanisms of non-specific resistance to syngeneic methylcholanthrene-induced fibrosarcomas of mice were investigated. Results showed that a small tumour graft of 0.05 X 10(5) cells is greatly enhanced in growth when admixed with large numbers of cell fragments, killed cells or viable non-replicating cells. The enhancement of small tumour grafts in cell mixtures was found to be non-specific. Carrageenan, a known anti-macrophage agent, significantly increased tumour growth in normal mice. However, it did not enhance the increased tumour growth of 0.05 X 10(5) cells mixed with 10(6) viable, non-replicating mitomycin C-treated tumour cells. The latter observation indicates that carrageenan and admixed cells interfere with the same tumour-inhibitory mechanism and therefore cannot produce additive effects. The results give support to the concept of a non-specific macrophage "surveillance" system which appears crucial in controlling tumour growth, since it determines the establishment of small numbers of tumour cells while they can still be easily destroyed.
D000818:Animals; D002351:Carrageenan / Q000494:pharmacology*; D002452:Cell Count; D005354:Fibrosarcoma / Q000276:immunology*; D007113:Immunity, Innate / Q000187:drug effects*; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D008937:Mitomycins / Q000494:pharmacology; D008938:Mitosis / Q000187:drug effects; D009368:Neoplasm Transplantation; D012513:Sarcoma, Experimental / Q000276:immunology; D014185:Transplantation, Isogeneic
D008937:Mitomycins; D002351:Carrageenan