Lipopolysaccharide (LPS)-stimulated spleen cells release colony-stimulating factor (CSF), a stimulator of granulopoiesis and macrophage formation in vitro. Colony-stimulating factor was assayed by the soft agar technique using murine bone marrow cells. A series of experiments was performed in order to identify the lymphoid cell type(s) which secrete CSF in response to LPS. Isolated peritoneal macrophages released high levels of CSF when cultured in vitro with this bacterial product. However, this secretory process was dependent on the degree of stimulation of the macrophage. Macrophages obtained from mice injected with thioglycollate or proteose peptone broth generated reduced levels of LPS-induced CSF in comparison with those detected in culture fluids of resident macrophages from control mice. Spleen cells or peritoneal macrophages from LPS-low responder mice of the strain C3H/HeJ secreted only small amounts of CSF upon stimulation with LPS. Column-filtered spleen cells depleted of macrophages had almost completely lost their ability to generate CSF, but when such cultures were supplemented with about 10% of proteose peptone-induced peritoneal macrophages, which generated themselves only minute levels of CSF, a strong granulopoietic activity was detected in the supernatants of the mixed cultures. Thus, CSF is released by LPS-stimulated isolated macrophages or as a result of some cellular interaction(s) between macrophages and lymphocytes in lymphoid cell cultures.
|Number of pages||10|
|Journal||RES Journal of the Reticuloendothelial Society|
|State||Published - 1 Dec 1979|