Meningococcal Outer Membrane Protein NhhA Triggers Apoptosis in Macrophages
Figure 4
NhhA-induced apoptosis in different cell types.
A: The pharyngeal epithelial cell line (FaDu) and the HL-60 promyelocytic leukemia cell line were exposed to 400 nM NhhA for 20 h. HL-60 cells were undifferentiated or differentiated to neutrophil-like cells by retinoic acid treatment (1 µM for 7 days, RA). B: The human monocytic cell line THP-1 was exposed to 400 nM NhhA. If indicated, THP-1 cells were differentiated to macrophages by treatment with PMA. Apoptotic cells were visualized using the APOPercentage kit and the relative numbers of apoptotic cells were determined by light microscopy. Values indicate mean±SD of three independent experiments. C: The human monocytic cell line THP-1 was exposed to 400 nM NhhA and apoptosis was measured by TCTF staining and flow cytometry. One representative experiment is shown.