Fig. 7.

Monocytes are the source for TNF in LPS-stimulated whole blood. To obtain different cell populations, total leucocyte fractions were obtained with dextran sedimentation of whole blood, while neutrophils and mononuclear cells were isolated from blood by Ficoll–Histopaque density gradient centrifugation. Monocytes were specifically depleted from the leucocyte fraction with anti-CD14 monoclonal antibody coated magnetic beads. The different cell fractions were challenged with 1 ng/ml LPS plus 1% NHS for 0 (black bars) and 45 min (open bars), centrifuged and the cell-free supernates reconstituted with fresh leucocytes in the presence of polymyxin B (to bind LPS) to determine the priming activity. Data from one typical experiment of three are given.