To characterize activation of immune cells, measurement of intracellular signaling using phospho-specific antibodies combined with immune phenotyping using surface markers is ideal. Owing to the unique capability of flow cytometry to measure events at a single-cell level, “Phospho Flow” allows for the identification of rare signaling events during processes such as co-stimulatory signaling and manipulation of checkpoint inhibition. However, combining extracellular and intracellular antibodies in a flow protocol can present technical challenges.
