EL-4 and macrophages: generation of chemotactic monokines

Various effects of EL-4 lymphoma supernatant fluids on macrophages were studied. Macrophages migrate under agarose to medium conditioned by the EL-4 cell line for up to 40 h. EL-4 conditioned medium after 67 h contained dialyzable migration inhibitors. In addition, upon direct treatment with the EL-4 supernatant, macrophages took on a more elongated or polarized morphology as compared to control medium or another tumour cell line conditioned medium. A 2 h treatment of macrophages with the EL-4 culture supernatant was sufficient to trigger the production and/or release of chemotactic monokines. These monokines were chemotactic for both PMNs and macrophages. In addition, a prior state of activation of the macrophage does not appear to be necessary for the production and/or release of the chemotactic monokines since resident as well as stimulated peritoneal macrophages are equally effective.