Fig. 4. LPS priming of monocytes induces a two-step clustering and multimerization of TREM-1.

a–b Isolated human monocytes were incubated at indicated times in resting conditions or stimulated with LPS (100 ng/ml) and/or cytochalasin D (5 µg/ml) when indicated. a Left panel: TREM-1 (green) and nucleus (TO-PRO-3, blue) staining by confocal microscopy after 3 and 24 h stimulation. Right panel: TREM-1 expression on isolated human monocytes after 24 h stimulation (scale bar: 10 µm). b Left panel: TREM-1 in situ PLA (red blobs) and nucleus (blue) by confocal microscopy after 3 and 24 h stimulation (scale bar: 10 µm). Right panel: quantification of average blobs/cell. Data information: data are representative of at least three independent experiments. MFI mean fluorescence intensity, ns nonsignificant. *p < 0.05, **p < 0.01, ***p < 0.001 vs. resting or as indicated, as determined by the two-tailed Student’s t-test