Specific inhibition of Mcl-1 abrogates the protective effect of TREM-1 against monocyte apoptosis. Adenovirus expressing TREM-1–infected THP-1 monocytic cells were cultured on TREM-1Ab– or phosphate-buffered saline–coated 24-well plate for 24 h, in combination with or without 0.6 μg/ml staurosporine and 20 µm Roscovitine for the last 4 h. Cells were stained with annexin V–fluorescein isothiocyanate/propidium iodide and analyzed by flow cytometry. The result is representative of three independent experiments (A) and data are presented as scatter plots with the mean imposed on the scatter (B). FITC = fluorescein isothiocyanate; Mcl-1 = myeloid cell leukemia-1; STS = staurosporine; TREM-1Ab = triggering receptor expressed on myeloid cells-1 antibody.