TNF-α Autocrine Feedback Loops in Human Monocytes: The Pro- and Anti-Inflammatory Roles of the TNF-α Receptors Support the Concept of Selective TNFR1 Blockade In Vivo

Figure 3

Pattern of TNF-α receptor expression on monocytes. Each column shows the mean percentage of monocytes (with SD bars) expressing each of the four possible cell surface receptor combinations, in freshly isolated cells and after stimulation with 100 ng/mL of LPS for 20 hours. Overall differences in receptor distribution subtype for each of the two conditions were assessed with separate Friedman’s tests and post hoc pairwise comparisons conducted if appropriate. In freshly isolated unstimulated monocytes, no overall difference was observed. In monocytes stimulated for 20 hours with 100 ng/mL of LPS, Friedman’s test was significant (). Significant post hoc values are shown in the figure and were significant for comparisons with monocytes expressing TNFR1 only. Comparisons for each of the four receptor distribution subtypes between freshly isolated and LPS-stimulated monocytes were conducted with Wilcoxon Signed-Ranks Testing and demonstrated an increase in the percentage of monocytes expressing neither receptor in LPS-stimulated cells. The experiments represent data from 6 subjects. Experimental conditions for freshly isolated monocytes were conducted singly and for LPS-stimulated monocytes in duplicate (due to limitations to cell numbers available).