Cytoplasmic transfer between endothelium and lymphocytes: quantitation by flow cytometry.

Interactions between human lymphocytes and vascular endothelial cells in coculture have been examined using a newly developed fluorescence flow cytometric technique. Endothelium and blood lymphocytes are capable of bidirectional transfer of a cytoplasmic fluorescent dye, suggesting a novel path of communication between circulating blood cells and the vessel wall. This method also may be applicable to the analysis of other heterocellular interactions.