Monocyte Differentiation towards Protumor Activity Does Not Correlate with M1 or M2 Phenotypes

Figure 4

Determination of phagocytosis. Phagocytic activity of THP-1, U937, and primary monocytes expressed as the median fluorescence intensity of fluorescein-labeled E. coli K-12 BioParticles engulfed by cells. Mean of three independent experiments is shown. For THP-1, mock: no stimulated cells; PMA: PMA-only control; M1: PMA + LPS + INF-γ; M2: PMA + IL-4 + IL-13; and M2 w/o PMA: IL-4 + IL-13. For U937, mock: no stimulated cells; PMA: PMA-only control; M1: PMA + LPS + INF-γ; M2-A: PMA + IL-4 + IL-13; M2-B: PMA + M-CSF; and M2-C: IL-4 + IL-13. For primary monocytes, mock: no stimulated cells; M1: GM-CSF + LPS + INF-γ; and M2: M-CSF + IL-4 + IL-13. Asterisks and bars denote statistical significance between conditions. Significance ≤0.05 was indicated with , and ≤0.0005 was indicated with . In THP-1 cells and primary monocytes there was statistically significant differences between M1 and M2 conditions and in U937 between M1 and M2-A and M2-B.