Flow cytometry intracellular markers, antibodies

Cell activation can lead to differentiation of certain cells into more mature cells that exhibit different structural and functional form. For example, immature hematopoietic cells can be stimulated by some proteins to mature, by changing cell morphology and by inducing expression of different intracellular and surface markers. Expression of differentiation markers can be detected and monitored by flow cytometry using specific antibodies against cell surface or intracellular markers. 

Flow cytometric determinations of P-selectin and activated GPIIb/llla receptor expression following ADP stimulation have been used to assess platelet inhibition by clopidogrel. Flow cytometry is also a cumbersome method and requires sophisticated instrumentation and well-trained technicians. The phosphorylation state of vasodilator-stimulated phos-phoprotein (VASP) is a specific intracellular marker of clopidogrel-induced P2Y 2 receptor inhibition and can also be measured by flow cytometry. Permeation of the membrane and the use of monoclonal antibodies specific for phosphory-lated VASP are required in this method (15,88). 

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