Granulocyte-monocyte-colony-stimulating factor augments the cytotoxic capacity of lymphocytes and monocytes in antibody-dependent cellular cytotoxicity.

Human peripheral blood mononuclear cells (lymphocytes and monocytes) were preincubated for 0-24 h with human recombinant granulocyte-monocyte-colony-stimulating factor (GM-CSF) and used as effector cells in an 18 h antibody-dependent cellular cytotoxicity (ADCC) assay with SW948 (a human colorectal carcinoma cell line) as target cells and mAb 17-1A. A significant increase in the lytic capability was noted after 0.5-2 h of preactivation while longer preincubation times did not significantly increase the lytic potential. GM-CSF at 0.01 microgram/ml induced the best tumor cell lysis while higher concentrations were inhibitory. GM-CSF pretreatment induced a statistically significant increase in the lytic capacity of both monocytes and lymphocytes in ADCC as well as in the spontaneous cytotoxicity.