title: In vitro effect of levan-activated macrophages on Lewis lung carcinoma cells.
abstract: The polysaccharide levan (polyfructose) has previously been shown to exert an inhibitory effect on the growth of several murine tumors. This activity is mediated by a host reaction, involving mainly macrophages but also other elements of the immune system. It was not clear, however, whether levan-activated macrophages act by a direct cytocidal effect on the tumor cells or via the activation of a specific immune response to the tumor. In the present study, the possibility of a direct cytotoxicity of levan-activated macrophages against Lewis lung carcinoma cells was tested by coculture in vitro. It was found that levan-induced (as well as paraffin oil induced) macrophages actually exert a direct cytotoxic effect on Lewis lung carcinoma cells. The tumor cell killing is mediated by cell to cell contact. A cytoplasmic bridge was often seen between the macrophage and the tumor cell. The remaining tumor cells in the lysed area appear slender, shrunken and non-dividing.
mesh_terms: D000818:Animals; D002450:Cell Communication; D003602:Cytotoxicity, Immunologic; D005630:Fructans; D008175:Lung Neoplasms / Q000276:immunology*; D008262:Macrophage Activation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D005630:Fructans