Flow cytometric analysis of intracellular phosphoproteins in human monocytes

Abstract

Background: Using antibodies against intracellular phosphoproteins, flow cytometry can be used to monitor simultaneously multiple signaling pathways. Here, we tested a recently released procedure to analyze phosphorylation events in human monocytes upon different types of stimulation. Methods: Whole blood was treated by lipopolysaccharide (LPS) or granulocyte-macrophage colony-stimulating factor (GM-CSF), then cells were labeled by antibodies recognizing cell surface and cytosolic proteins. Human monocytes were identified by a CD14 – CD45 staining and three phosphorylated proteins such as AKT, ERK-1/2, and STAT5, were simultaneously detected by multicolor phosphoflow analysis. Results: By this rapid method, we are able to detect directly from a blood sample several signaling events in human monocytes where LPS stimulation induces preferentially ERK-1/2 phosphorylation where as GM-CSF stimulation induces STAT5 phosphorylation. Conclusions: This procedure provides a simultaneous measurement of multiple activated signaling molecules using a simplified and rapid protocol. © 2015 International Clinical Cytometry Society.