Secretion of (A) TNF-alpha, (B) IL-12, and (C) IL-10 by monocytes pretreated with different agents before coculture and restimulation with tumor cells (protocol 1). Cytokine release by tumor cell-stimulated monocytes (control response) was 4348 ± 860 pg/ml, 873 ± 346 pg/ml, and 2662 ± 963 pg/ml for TNF-alpha, IL-12 (p40), and IL-10, respectively. Cytokine release by monocytes preexposed and restimulated with tumor cells (medium) was 1507 ± 979 pg/ml, 110 ± 91 pg/ml, and 4166 ± 1104 pg/ml for TNF-alpha, IL-12 (p40), and IL-10, respectively. Mean cytokine release by control monocytes pretreated with different agents was 235 ± 372 pg/ml, 11 ± 39 pg/ml, and 9 ± 40 pg/ml for TNF-alpha, IL-12 (p40), and IL-10, respectively. The results are expressed as a percentage of the response obtained for control monocytes stimulated with tumor cells. The means from 8-10 independent experiments are shown, with error bars corresponding to 1 SD.