Hydrocortisone at 10-4 M added to macrophage cell lines had no effect on the following activities: J774.1 antibody-dependent phagocytosis and lysis of sheep RBC, RAW 264 antibody-dependent lysis of tumor targets, latex bead phagocytosis by PU5-1.8 cells, and constitutive production of myeloid colony-stimulating activity (CSA) by WEHI-3 cells. In contrast, 10-4 M hydrocortisone completely inhibited LPS or PPD activation of the following functions: induced production of myeloid CSA, stimulation of latex phagocytosis and stimulation of antibody-dependent lysis of tumor targets by PU5-1.8 cell line, and stimulation of antibody-dependent lysis of RBC targets by RAW 264 cell line. Lower concentrations of hydrocortisone or dexamethasone at 10-6 M inhibited the LPS induction of CSA from 55 to 90%. Growth inhibition of PU5-1.8 cells caused by 1 µg/ml LPS was also partially reversed by corticosteroids. Thus, steroids block these newly induced but not constitutive functions of these macrophage cells in culture.

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This work was supported by National Science Foundation Grant PCM75-19734, National Cancer Institute Grants CA 17353 and CA 17085, and the Gar Reichman Foundation.

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