Kinetic flow cytometric analysis showing the effect of IR and LPS on mTNF-α expression on PBMCs and the protective role of IL-10. PBMCs were either untreated (Control), irradiated (IR), or incubated with LPS in the presence or absence of IL-10. Results are shown as the percentage of mTNF-α⁺ cells, with staining for mTNF-α at 1, 4, and 24 hours after treatment as described in the Materials and Methods. Results representative of three independent experiments are shown. (Histogram inserts) Only the monocytic CD14⁺ subpopulation expresses mTNF-α. Flow cytometric analysis with a costaining of PBMCs with anti–TNF-α and anti-CD14 MoAbs. Dotted line, isotype-matched control antibody; solid thin line, staining with anti-CD14; solid thick line, staining with anti–TNF-α.